codemirror
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In-browser code editing made bearable
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<ul>
<li><a href="../index.html">Home</a></li>
<li><a href="#overview" class=active data-default="true">Manual</a></li>
<li><a href="https://github.com/marijnh/codemirror">Code</a></li>
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<ul>
<li><a href="#usage">Basic Usage</a></li>
<li><a href="#config">Configuration</a></li>
<li><a href="#events">Events</a></li>
<li><a href="#keymaps">Keymaps</a></li>
<li><a href="#styling">Customized Styling</a></li>
<li><a href="#api">Programming API</a>
<ul>
<li><a href="#api_constructor">Constructor</a></li>
<li><a href="#api_content">Content manipulation</a></li>
<li><a href="#api_selection">Selection</a></li>
<li><a href="#api_configuration">Configuration</a></li>
<li><a href="#api_doc">Document management</a></li>
<li><a href="#api_history">History</a></li>
<li><a href="#api_marker">Text-marking</a></li>
<li><a href="#api_decoration">Widget, gutter, and decoration</a></li>
<li><a href="#api_sizing">Sizing, scrolling, and positioning</a></li>
<li><a href="#api_mode">Mode, state, and tokens</a></li>
<li><a href="#api_misc">Miscellaneous methods</a></li>
<li><a href="#api_static">Static properties</a></li>
</ul>
</li>
<li><a href="#addons">Addons</a></li>
<li><a href="#modeapi">Writing CodeMirror Modes</a></li>
</ul>
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<article>
<section class=first id=overview>
<h2 style="position: relative">
User manual and reference guide
<span style="color: #888; font-size: 1rem; position: absolute; right: 0; bottom: 0">version 3.24.0</span>
</h2>
<p>CodeMirror is a code-editor component that can be embedded in
Web pages. The core library provides <em>only</em> the editor
component, no accompanying buttons, auto-completion, or other IDE
functionality. It does provide a rich API on top of which such
functionality can be straightforwardly implemented. See
the <a href="#addons">addons</a> included in the distribution,
and the <a href="https://github.com/marijnh/CodeMirror/wiki/CodeMirror-addons">list
of externally hosted addons</a>, for reusable
implementations of extra features.</p>
<p>CodeMirror works with language-specific modes. Modes are
JavaScript programs that help color (and optionally indent) text
written in a given language. The distribution comes with a number
of modes (see the <a href="../mode/"><code>mode/</code></a>
directory), and it isn't hard to <a href="#modeapi">write new
ones</a> for other languages.</p>
</section>
<section id=usage>
<h2>Basic Usage</h2>
<p>The easiest way to use CodeMirror is to simply load the script
and style sheet found under <code>lib/</code> in the distribution,
plus a mode script from one of the <code>mode/</code> directories.
(See <a href="compress.html">the compression helper</a> for an
easy way to combine scripts.) For example:</p>
<pre data-lang="text/html"><script src="lib/codemirror.js"></script>
<link rel="stylesheet" href="../lib/codemirror.css">
<script src="mode/javascript/javascript.js"></script></pre>
<p>Having done this, an editor instance can be created like
this:</p>
<pre data-lang="javascript">var myCodeMirror = CodeMirror(document.body);</pre>
<p>The editor will be appended to the document body, will start
empty, and will use the mode that we loaded. To have more control
over the new editor, a configuration object can be passed
to <a href="#CodeMirror"><code>CodeMirror</code></a> as a second
argument:</p>
<pre data-lang="javascript">var myCodeMirror = CodeMirror(document.body, {
value: "function myScript(){return 100;}\n",
mode: "javascript"
});</pre>
<p>This will initialize the editor with a piece of code already in
it, and explicitly tell it to use the JavaScript mode (which is
useful when multiple modes are loaded).
See <a href="#config">below</a> for a full discussion of the
configuration options that CodeMirror accepts.</p>
<p>In cases where you don't want to append the editor to an
element, and need more control over the way it is inserted, the
first argument to the <code>CodeMirror</code> function can also
be a function that, when given a DOM element, inserts it into the
document somewhere. This could be used to, for example, replace a
textarea with a real editor:</p>
<pre data-lang="javascript">var myCodeMirror = CodeMirror(function(elt) {
myTextArea.parentNode.replaceChild(elt, myTextArea);
}, {value: myTextArea.value});</pre>
<p>However, for this use case, which is a common way to use
CodeMirror, the library provides a much more powerful
shortcut:</p>
<pre data-lang="javascript">var myCodeMirror = CodeMirror.fromTextArea(myTextArea);</pre>
<p>This will, among other things, ensure that the textarea's value
is updated with the editor's contents when the form (if it is part
of a form) is submitted. See the <a href="#fromTextArea">API
reference</a> for a full description of this method.</p>
</section>
<section id=config>
<h2>Configuration</h2>
<p>Both the <a href="#CodeMirror"><code>CodeMirror</code></a>
function and its <code>fromTextArea</code> method take as second
(optional) argument an object containing configuration options.
Any option not supplied like this will be taken
from <a href="#defaults"><code>CodeMirror.defaults</code></a>, an
object containing the default options. You can update this object
to change the defaults on your page.</p>
<p>Options are not checked in any way, so setting bogus option
values is bound to lead to odd errors.</p>
<p>These are the supported options:</p>
<dl>
<dt id="option_value"><code><strong>value</strong>: string|CodeMirror.Doc</code></dt>
<dd>The starting value of the editor. Can be a string, or
a <a href="#api_doc">document object</a>.</dd>
<dt id="option_mode"><code><strong>mode</strong>: string|object</code></dt>
<dd>The mode to use. When not given, this will default to the
first mode that was loaded. It may be a string, which either
simply names the mode or is
a <a href="http://en.wikipedia.org/wiki/MIME">MIME</a> type
associated with the mode. Alternatively, it may be an object
containing configuration options for the mode, with
a <code>name</code> property that names the mode (for
example <code>{name: "javascript", json: true}</code>). The demo
pages for each mode contain information about what configuration
parameters the mode supports. You can ask CodeMirror which modes
and MIME types have been defined by inspecting
the <code>CodeMirror.modes</code>
and <code>CodeMirror.mimeModes</code> objects. The first maps
mode names to their constructors, and the second maps MIME types
to mode specs.</dd>
<dt id="option_theme"><code><strong>theme</strong>: string</code></dt>
<dd>The theme to style the editor with. You must make sure the
CSS file defining the corresponding <code>.cm-s-[name]</code>
styles is loaded (see
the <a href="../theme/"><code>theme</code></a> directory in the
distribution). The default is <code>"default"</code>, for which
colors are included in <code>codemirror.css</code>. It is
possible to use multiple theming classes at once—for
example <code>"foo bar"</code> will assign both
the <code>cm-s-foo</code> and the <code>cm-s-bar</code> classes
to the editor.</dd>
<dt id="option_indentUnit"><code><strong>indentUnit</strong>: integer</code></dt>
<dd>How many spaces a block (whatever that means in the edited
language) should be indented. The default is 2.</dd>
<dt id="option_smartIndent"><code><strong>smartIndent</strong>: boolean</code></dt>
<dd>Whether to use the context-sensitive indentation that the
mode provides (or just indent the same as the line before).
Defaults to true.</dd>
<dt id="option_tabSize"><code><strong>tabSize</strong>: integer</code></dt>
<dd>The width of a tab character. Defaults to 4.</dd>
<dt id="option_indentWithTabs"><code><strong>indentWithTabs</strong>: boolean</code></dt>
<dd>Whether, when indenting, the first N*<code>tabSize</code>
spaces should be replaced by N tabs. Default is false.</dd>
<dt id="option_electricChars"><code><strong>electricChars</strong>: boolean</code></dt>
<dd>Configures whether the editor should re-indent the current
line when a character is typed that might change its proper
indentation (only works if the mode supports indentation).
Default is true.</dd>
<dt id="option_specialChars"><code><strong>specialChars</strong>: RegExp</code></dt>
<dd>A regular expression used to determine which characters
should be replaced by a
special <a href="#option_specialCharPlaceholder">placeholder</a>.
Mostly useful for non-printing special characters. The default
is <code>/[\u0000-\u0019\u00ad\u200b\u2028\u2029\ufeff]/</code>.</dd>
<dt id="option_specialCharPlaceholder"><code><strong>specialCharPlaceholder</strong>: function(char) → Element</code></dt>
<dd>A function that, given a special character identified by
the <a href="#option_specialChars"><code>specialChars</code></a>
option, produces a DOM node that is used to represent the
character. By default, a red dot (<span style="color: red">•</span>)
is shown, with a title tooltip to indicate the character code.</dd>
<dt id="option_rtlMoveVisually"><code><strong>rtlMoveVisually</strong>: boolean</code></dt>
<dd>Determines whether horizontal cursor movement through
right-to-left (Arabic, Hebrew) text is visual (pressing the left
arrow moves the cursor left) or logical (pressing the left arrow
moves to the next lower index in the string, which is visually
right in right-to-left text). The default is <code>false</code>
on Windows, and <code>true</code> on other platforms.</dd>
<dt id="option_keyMap"><code><strong>keyMap</strong>: string</code></dt>
<dd>Configures the keymap to use. The default
is <code>"default"</code>, which is the only keymap defined
in <code>codemirror.js</code> itself. Extra keymaps are found in
the <a href="../keymap/"><code>keymap</code></a> directory. See
the <a href="#keymaps">section on keymaps</a> for more
information.</dd>
<dt id="option_extraKeys"><code><strong>extraKeys</strong>: object</code></dt>
<dd>Can be used to specify extra keybindings for the editor,
alongside the ones defined
by <a href="#option_keyMap"><code>keyMap</code></a>. Should be
either null, or a valid <a href="#keymaps">keymap</a> value.</dd>
<dt id="option_lineWrapping"><code><strong>lineWrapping</strong>: boolean</code></dt>
<dd>Whether CodeMirror should scroll or wrap for long lines.
Defaults to <code>false</code> (scroll).</dd>
<dt id="option_lineNumbers"><code><strong>lineNumbers</strong>: boolean</code></dt>
<dd>Whether to show line numbers to the left of the editor.</dd>
<dt id="option_firstLineNumber"><code><strong>firstLineNumber</strong>: integer</code></dt>
<dd>At which number to start counting lines. Default is 1.</dd>
<dt id="option_lineNumberFormatter"><code><strong>lineNumberFormatter</strong>: function(line: integer) → string</code></dt>
<dd>A function used to format line numbers. The function is
passed the line number, and should return a string that will be
shown in the gutter.</dd>
<dt id="option_gutters"><code><strong>gutters</strong>: array<string></code></dt>
<dd>Can be used to add extra gutters (beyond or instead of the
line number gutter). Should be an array of CSS class names, each
of which defines a <code>width</code> (and optionally a
background), and which will be used to draw the background of
the gutters. <em>May</em> include
the <code>CodeMirror-linenumbers</code> class, in order to
explicitly set the position of the line number gutter (it will
default to be to the right of all other gutters). These class
names are the keys passed
to <a href="#setGutterMarker"><code>setGutterMarker</code></a>.</dd>
<dt id="option_fixedGutter"><code><strong>fixedGutter</strong>: boolean</code></dt>
<dd>Determines whether the gutter scrolls along with the content
horizontally (false) or whether it stays fixed during horizontal
scrolling (true, the default).</dd>
<dt id="option_coverGutterNextToScrollbar"><code><strong>coverGutterNextToScrollbar</strong>: boolean</code></dt>
<dd>When <a href="#option_fixedGutter"><code>fixedGutter</code></a>
is on, and there is a horizontal scrollbar, by default the
gutter will be visible to the left of this scrollbar. If this
option is set to true, it will be covered by an element with
class <code>CodeMirror-gutter-filler</code>.</dd>
<dt id="option_readOnly"><code><strong>readOnly</strong>: boolean|string</code></dt>
<dd>This disables editing of the editor content by the user. If
the special value <code>"nocursor"</code> is given (instead of
simply <code>true</code>), focusing of the editor is also
disallowed.</dd>
<dt id="option_showCursorWhenSelecting"><code><strong>showCursorWhenSelecting</strong>: boolean</code></dt>
<dd>Whether the cursor should be drawn when a selection is
active. Defaults to false.</dd>
<dt id="option_undoDepth"><code><strong>undoDepth</strong>: integer</code></dt>
<dd>The maximum number of undo levels that the editor stores.
Defaults to 40.</dd>
<dt id="option_historyEventDelay"><code><strong>historyEventDelay</strong>: integer</code></dt>
<dd>The period of inactivity (in milliseconds) that will cause a
new history event to be started when typing or deleting.
Defaults to 500.</dd>
<dt id="option_tabindex"><code><strong>tabindex</strong>: integer</code></dt>
<dd>The <a href="http://www.w3.org/TR/html401/interact/forms.html#adef-tabindex">tab
index</a> to assign to the editor. If not given, no tab index
will be assigned.</dd>
<dt id="option_autofocus"><code><strong>autofocus</strong>: boolean</code></dt>
<dd>Can be used to make CodeMirror focus itself on
initialization. Defaults to off.
When <a href="#fromTextArea"><code>fromTextArea</code></a> is
used, and no explicit value is given for this option, it will be
set to true when either the source textarea is focused, or it
has an <code>autofocus</code> attribute and no other element is
focused.</dd>
</dl>
<p>Below this a few more specialized, low-level options are
listed. These are only useful in very specific situations, you
might want to skip them the first time you read this manual.</p>
<dl>
<dt id="option_dragDrop"><code><strong>dragDrop</strong>: boolean</code></dt>
<dd>Controls whether drag-and-drop is enabled. On by default.</dd>
<dt id="option_onDragEvent"><code><strong>onDragEvent</strong>: function(instance: CodeMirror, event: Event) → boolean</code></dt>
<dd><em>Deprecated! See <a href="#event_dom">these</a> event
handlers for the current recommended approach.</em><br>When given,
this will be called when the editor is handling
a <code>dragenter</code>, <code>dragover</code>,
or <code>drop</code> event. It will be passed the editor
instance and the event object as arguments. The callback can
choose to handle the event itself, in which case it should
return <code>true</code> to indicate that CodeMirror should not
do anything further.</dd>
<dt id="option_onKeyEvent"><code><strong>onKeyEvent</strong>: function(instance: CodeMirror, event: Event) → boolean</code></dt>
<dd><em>Deprecated! See <a href="#event_dom">these</a> event
handlers for the current recommended approach.</em><br>This
provides a rather low-level hook into CodeMirror's key handling.
If provided, this function will be called on
every <code>keydown</code>, <code>keyup</code>,
and <code>keypress</code> event that CodeMirror captures. It
will be passed two arguments, the editor instance and the key
event. This key event is pretty much the raw key event, except
that a <code>stop()</code> method is always added to it. You
could feed it to, for example, <code>jQuery.Event</code> to
further normalize it.<br>This function can inspect the key
event, and handle it if it wants to. It may return true to tell
CodeMirror to ignore the event. Be wary that, on some browsers,
stopping a <code>keydown</code> does not stop
the <code>keypress</code> from firing, whereas on others it
does. If you respond to an event, you should probably inspect
its <code>type</code> property and only do something when it
is <code>keydown</code> (or <code>keypress</code> for actions
that need character data).</dd>
<dt id="option_cursorBlinkRate"><code><strong>cursorBlinkRate</strong>: number</code></dt>
<dd>Half-period in milliseconds used for cursor blinking. The default blink
rate is 530ms. By setting this to zero, blinking can be disabled.</dd>
<dt id="option_cursorScrollMargin"><code><strong>cursorScrollMargin</strong>: number</code></dt>
<dd>How much extra space to always keep above and below the
cursor when approaching the top or bottom of the visible view in
a scrollable document. Default is 0.</dd>
<dt id="option_cursorHeight"><code><strong>cursorHeight</strong>: number</code></dt>
<dd>Determines the height of the cursor. Default is 1, meaning
it spans the whole height of the line. For some fonts (and by
some tastes) a smaller height (for example <code>0.85</code>),
which causes the cursor to not reach all the way to the bottom
of the line, looks better</dd>
<dt id="option_resetSelectionOnContextMenu"><code><strong>resetSelectionOnContextMenu</strong>: boolean</code></dt>
<dd>Controls whether, when the context menu is opened with a
click outside of the current selection, the cursor is moved to
the point of the click. Defaults to <code>true</code>.</dd>
<dt id="option_workTime"><code><strong>workTime</strong>, <strong>workDelay</strong>: number</code></dt>
<dd>Highlighting is done by a pseudo background-thread that will
work for <code>workTime</code> milliseconds, and then use
timeout to sleep for <code>workDelay</code> milliseconds. The
defaults are 200 and 300, you can change these options to make
the highlighting more or less aggressive.</dd>
<dt id="option_workDelay"><code><strong>workDelay</strong>: number</code></dt>
<dd>See <a href="#option_workTime"><code>workTime</code></a>.</dd>
<dt id="option_pollInterval"><code><strong>pollInterval</strong>: number</code></dt>
<dd>Indicates how quickly CodeMirror should poll its input
textarea for changes (when focused). Most input is captured by
events, but some things, like IME input on some browsers, don't
generate events that allow CodeMirror to properly detect it.
Thus, it polls. Default is 100 milliseconds.</dd>
<dt id="option_flattenSpans"><code><strong>flattenSpans</strong>: boolean</code></dt>
<dd>By default, CodeMirror will combine adjacent tokens into a
single span if they have the same class. This will result in a
simpler DOM tree, and thus perform better. With some kinds of
styling (such as rounded corners), this will change the way the
document looks. You can set this option to false to disable this
behavior.</dd>
<dt id="option_addModeClass"><code><strong>addModeClass</strong>: boolean</code></dt>
<dd>When enabled (off by default), an extra CSS class will be
added to each token, indicating the
(<a href="#innerMode">inner</a>) mode that produced it, prefixed
with <code>"cm-m-"</code>. For example, tokens from the XML mode
will get the <code>cm-m-xml</code> class.</dd>
<dt id="option_maxHighlightLength"><code><strong>maxHighlightLength</strong>: number</code></dt>
<dd>When highlighting long lines, in order to stay responsive,
the editor will give up and simply style the rest of the line as
plain text when it reaches a certain position. The default is
10 000. You can set this to <code>Infinity</code> to turn off
this behavior.</dd>
<dt id="option_crudeMeasuringFrom"><code><strong>crudeMeasuringFrom</strong>: number</code></dt>
<dd>When measuring the character positions in long lines, any
line longer than this number (default is 10 000),
when <a href="#option_lineWrapping">line wrapping</a>
is <strong>off</strong>, will simply be assumed to consist of
same-sized characters. This means that, on the one hand,
measuring will be inaccurate when characters of varying size,
right-to-left text, markers, or other irregular elements are
present. On the other hand, it means that having such a line
won't freeze the user interface because of the expensiveness of
the measurements.</dd>
<dt id="option_viewportMargin"><code><strong>viewportMargin</strong>: integer</code></dt>
<dd>Specifies the amount of lines that are rendered above and
below the part of the document that's currently scrolled into
view. This affects the amount of updates needed when scrolling,
and the amount of work that such an update does. You should
usually leave it at its default, 10. Can be set
to <code>Infinity</code> to make sure the whole document is
always rendered, and thus the browser's text search works on it.
This <em>will</em> have bad effects on performance of big
documents.</dd>
</dl>
</section>
<section id=events>
<h2>Events</h2>
<p>Various CodeMirror-related objects emit events, which allow
client code to react to various situations. Handlers for such
events can be registered with the <a href="#on"><code>on</code></a>
and <a href="#off"><code>off</code></a> methods on the objects
that the event fires on. To fire your own events,
use <code>CodeMirror.signal(target, name, args...)</code>,
where <code>target</code> is a non-DOM-node object.</p>
<p>An editor instance fires the following events.
The <code>instance</code> argument always refers to the editor
itself.</p>
<dl>
<dt id="event_change"><code><strong>"change"</strong> (instance: CodeMirror, changeObj: object)</code></dt>
<dd>Fires every time the content of the editor is changed.
The <code>changeObj</code> is a <code>{from, to, text, removed,
next}</code> object containing information about the changes
that occurred as second argument. <code>from</code>
and <code>to</code> are the positions (in the pre-change
coordinate system) where the change started and ended (for
example, it might be <code>{ch:0, line:18}</code> if the
position is at the beginning of line #19). <code>text</code> is
an array of strings representing the text that replaced the
changed range (split by line). <code>removed</code> is the text
that used to be between <code>from</code> and <code>to</code>,
which is overwritten by this change. If multiple changes
happened during a single operation, the object will have
a <code>next</code> property pointing to another change object
(which may point to another, etc).</dd>
<dt id="event_beforeChange"><code><strong>"beforeChange"</strong> (instance: CodeMirror, changeObj: object)</code></dt>
<dd>This event is fired before a change is applied, and its
handler may choose to modify or cancel the change.
The <code>changeObj</code> object
has <code>from</code>, <code>to</code>, and <code>text</code>
properties, as with
the <a href="#event_change"><code>"change"</code></a> event, but
never a <code>next</code> property, since this is fired for each
individual change, and not batched per operation. It also has
a <code>cancel()</code> method, which can be called to cancel
the change, and, <strong>if</strong> the change isn't coming
from an undo or redo event, an <code>update(from, to,
text)</code> method, which may be used to modify the change.
Undo or redo changes can't be modified, because they hold some
metainformation for restoring old marked ranges that is only
valid for that specific change. All three arguments
to <code>update</code> are optional, and can be left off to
leave the existing value for that field
intact. <strong>Note:</strong> you may not do anything from
a <code>"beforeChange"</code> handler that would cause changes
to the document or its visualization. Doing so will, since this
handler is called directly from the bowels of the CodeMirror
implementation, probably cause the editor to become
corrupted.</dd>
<dt id="event_cursorActivity"><code><strong>"cursorActivity"</strong> (instance: CodeMirror)</code></dt>
<dd>Will be fired when the cursor or selection moves, or any
change is made to the editor content.</dd>
<dt id="event_keyHandled"><code><strong>"keyHandled"</strong> (instance: CodeMirror, name: string, event: Event)</code></dt>
<dd>Fired after a key is handled through a
keymap. <code>name</code> is the name of the handled key (for
example <code>"Ctrl-X"</code> or <code>"'q'"</code>),
and <code>event</code> is the DOM <code>keydown</code>
or <code>keypress</code> event.</dd>
<dt id="event_inputRead"><code><strong>"inputRead"</strong> (instance: CodeMirror, changeObj: object)</code></dt>
<dd>Fired whenever new input is read from the hidden textarea
(typed or pasted by the user).</dd>
<dt id="event_beforeSelectionChange"><code><strong>"beforeSelectionChange"</strong> (instance: CodeMirror, selection: {head, anchor})</code></dt>
<dd>This event is fired before the selection is moved. Its
handler may modify the resulting selection head and anchor.
The <code>selection</code> parameter is an object
with <code>head</code> and <code>anchor</code> properties
holding <code>{line, ch}</code> objects, which the handler can
read and update. Handlers for this event have the same
restriction
as <a href="#event_beforeChange"><code>"beforeChange"</code></a>
handlers — they should not do anything to directly update the
state of the editor.</dd>
<dt id="event_viewportChange"><code><strong>"viewportChange"</strong> (instance: CodeMirror, from: number, to: number)</code></dt>
<dd>Fires whenever the <a href="#getViewport">view port</a> of
the editor changes (due to scrolling, editing, or any other
factor). The <code>from</code> and <code>to</code> arguments
give the new start and end of the viewport.</dd>
<dt id="event_swapDoc"><code><strong>"swapDoc"</strong> (instance: CodeMirror, oldDoc: Doc)</code></dt>
<dd>This is signalled when the editor's document is replaced
using the <a href="#swapDoc"><code>swapDoc</code></a>
method.</dd>
<dt id="event_gutterClick"><code><strong>"gutterClick"</strong> (instance: CodeMirror, line: integer, gutter: string, clickEvent: Event)</code></dt>
<dd>Fires when the editor gutter (the line-number area) is
clicked. Will pass the editor instance as first argument, the
(zero-based) number of the line that was clicked as second
argument, the CSS class of the gutter that was clicked as third
argument, and the raw <code>mousedown</code> event object as
fourth argument.</dd>
<dt id="event_gutterContextMenu"><code><strong>"gutterContextMenu"</strong> (instance: CodeMirror, line: integer, gutter: string, contextMenu: Event: Event)</code></dt>
<dd>Fires when the editor gutter (the line-number area)
receives a <code>contextmenu</code> event. Will pass the editor
instance as first argument, the (zero-based) number of the line
that was clicked as second argument, the CSS class of the
gutter that was clicked as third argument, and the raw
<code>contextmenu</code> mouse event object as fourth argument.
You can <code>preventDefault</code> the event, to signal that
CodeMirror should do no further handling.</dd>
<dt id="event_focus"><code><strong>"focus"</strong> (instance: CodeMirror)</code></dt>
<dd>Fires whenever the editor is focused.</dd>
<dt id="event_blur"><code><strong>"blur"</strong> (instance: CodeMirror)</code></dt>
<dd>Fires whenever the editor is unfocused.</dd>
<dt id="event_scroll"><code><strong>"scroll"</strong> (instance: CodeMirror)</code></dt>
<dd>Fires when the editor is scrolled.</dd>
<dt id="event_update"><code><strong>"update"</strong> (instance: CodeMirror)</code></dt>
<dd>Will be fired whenever CodeMirror updates its DOM display.</dd>
<dt id="event_renderLine"><code><strong>"renderLine"</strong> (instance: CodeMirror, line: LineHandle, element: Element)</code></dt>
<dd>Fired whenever a line is (re-)rendered to the DOM. Fired
right after the DOM element is built, <em>before</em> it is
added to the document. The handler may mess with the style of
the resulting element, or add event handlers, but
should <em>not</em> try to change the state of the editor.</dd>
<dt id="event_dom"><code><strong>"mousedown"</strong>,
<strong>"dblclick"</strong>, <strong>"contextmenu"</strong>, <strong>"keydown"</strong>, <strong>"keypress"</strong>,
<strong>"keyup"</strong>, <strong>"dragstart"</strong>, <strong>"dragenter"</strong>,
<strong>"dragover"</strong>, <strong>"drop"</strong>
(instance: CodeMirror, event: Event)</code></dt>
<dd>Fired when CodeMirror is handling a DOM event of this type.
You can <code>preventDefault</code> the event, or give it a
truthy <code>codemirrorIgnore</code> property, to signal that
CodeMirror should do no further handling.</dd>
</dl>
<p>Document objects (instances
of <a href="#Doc"><code>CodeMirror.Doc</code></a>) emit the
following events:</p>
<dl>
<dt id="event_doc_change"><code><strong>"change"</strong> (doc: CodeMirror.Doc, changeObj: object)</code></dt>
<dd>Fired whenever a change occurs to the
document. <code>changeObj</code> has a similar type as the
object passed to the
editor's <a href="#event_change"><code>"change"</code></a>
event, but it never has a <code>next</code> property, because
document change events are not batched (whereas editor change
events are).</dd>
<dt id="event_doc_beforeChange"><code><strong>"beforeChange"</strong> (doc: CodeMirror.Doc, change: object)</code></dt>
<dd>See the <a href="#event_beforeChange">description of the
same event</a> on editor instances.</dd>
<dt id="event_doc_cursorActivity"><code><strong>"cursorActivity"</strong> (doc: CodeMirror.Doc)</code></dt>
<dd>Fired whenever the cursor or selection in this document
changes.</dd>
<dt id="event_doc_beforeSelectionChange"><code><strong>"beforeSelectionChange"</strong> (doc: CodeMirror.Doc, selection: {head, anchor})</code></dt>
<dd>Equivalent to
the <a href="#event_beforeSelectionChange">event by the same
name</a> as fired on editor instances.</dd>
</dl>
<p>Line handles (as returned by, for
example, <a href="#getLineHandle"><code>getLineHandle</code></a>)
support these events:</p>
<dl>
<dt id="event_delete"><code><strong>"delete"</strong> ()</code></dt>
<dd>Will be fired when the line object is deleted. A line object
is associated with the <em>start</em> of the line. Mostly useful
when you need to find out when your <a href="#setGutterMarker">gutter
markers</a> on a given line are removed.</dd>
<dt id="event_line_change"><code><strong>"change"</strong> (line: LineHandle, changeObj: object)</code></dt>
<dd>Fires when the line's text content is changed in any way
(but the line is not deleted outright). The <code>change</code>
object is similar to the one passed
to <a href="#event_change">change event</a> on the editor
object.</dd>
</dl>
<p>Marked range handles (<code>CodeMirror.TextMarker</code>), as returned
by <a href="#markText"><code>markText</code></a>
and <a href="#setBookmark"><code>setBookmark</code></a>, emit the
following events:</p>
<dl>
<dt id="event_beforeCursorEnter"><code><strong>"beforeCursorEnter"</strong> ()</code></dt>
<dd>Fired when the cursor enters the marked range. From this
event handler, the editor state may be inspected
but <em>not</em> modified, with the exception that the range on
which the event fires may be cleared.</dd>
<dt id="event_clear"><code><strong>"clear"</strong> (from: {line, ch}, to: {line, ch})</code></dt>
<dd>Fired when the range is cleared, either through cursor
movement in combination
with <a href="#mark_clearOnEnter"><code>clearOnEnter</code></a>
or through a call to its <code>clear()</code> method. Will only
be fired once per handle. Note that deleting the range through
text editing does not fire this event, because an undo action
might bring the range back into existence. <code>from</code>
and <code>to</code> give the part of the document that the range
spanned when it was cleared.</dd>
<dt id="event_hide"><code><strong>"hide"</strong> ()</code></dt>
<dd>Fired when the last part of the marker is removed from the
document by editing operations.</dd>
<dt id="event_unhide"><code><strong>"unhide"</strong> ()</code></dt>
<dd>Fired when, after the marker was removed by editing, a undo
operation brought the marker back.</dd>
</dl>
<p>Line widgets (<code>CodeMirror.LineWidget</code>), returned
by <a href="#addLineWidget"><code>addLineWidget</code></a>, fire
these events:</p>
<dl>
<dt id="event_redraw"><code><strong>"redraw"</strong> ()</code></dt>
<dd>Fired whenever the editor re-adds the widget to the DOM.
This will happen once right after the widget is added (if it is
scrolled into view), and then again whenever it is scrolled out
of view and back in again, or when changes to the editor options
or the line the widget is on require the widget to be
redrawn.</dd>
</dl>
</section>
<section id=keymaps>
<h2>Keymaps</h2>
<p>Keymaps are ways to associate keys with functionality. A keymap
is an object mapping strings that identify the keys to functions
that implement their functionality.</p>
<p>Keys are identified either by name or by character.
The <code>CodeMirror.keyNames</code> object defines names for
common keys and associates them with their key codes. Examples of
names defined here are <code>Enter</code>, <code>F5</code>,
and <code>Q</code>. These can be prefixed
with <code>Shift-</code>, <code>Cmd-</code>, <code>Ctrl-</code>,
and <code>Alt-</code> (in that order!) to specify a modifier. So
for example, <code>Shift-Ctrl-Space</code> would be a valid key
identifier.</p>
<p>Common example: map the Tab key to insert spaces instead of a tab
character.</p>
<pre data-lang="javascript">
{
Tab: function(cm) {
var spaces = Array(cm.getOption("indentUnit") + 1).join(" ");
cm.replaceSelection(spaces, "end", "+input");
}
}</pre>
<p>Alternatively, a character can be specified directly by
surrounding it in single quotes, for example <code>'$'</code>
or <code>'q'</code>. Due to limitations in the way browsers fire
key events, these may not be prefixed with modifiers.</p>
<p>The <code>CodeMirror.keyMap</code> object associates keymaps
with names. User code and keymap definitions can assign extra
properties to this object. Anywhere where a keymap is expected, a
string can be given, which will be looked up in this object. It
also contains the <code>"default"</code> keymap holding the
default bindings.</p>
<p id="commands">The values of properties in keymaps can be either functions of
a single argument (the CodeMirror instance), strings, or
<code>false</code>. Such strings refer to properties of the
<code>CodeMirror.commands</code> object, which defines a number of
common commands that are used by the default keybindings, and maps
them to functions. If the property is set to <code>false</code>,
CodeMirror leaves handling of the key up to the browser. A key
handler function may return <code>CodeMirror.Pass</code> to indicate
that it has decided not to handle the key, and other handlers (or
the default behavior) should be given a turn.</p>
<p>Keys mapped to command names that start with the
characters <code>"go"</code> (which should be used for
cursor-movement actions) will be fired even when an
extra <code>Shift</code> modifier is present (i.e. <code>"Up":
"goLineUp"</code> matches both up and shift-up). This is used to
easily implement shift-selection.</p>
<p>Keymaps can defer to each other by defining
a <code>fallthrough</code> property. This indicates that when a
key is not found in the map itself, one or more other maps should
be searched. It can hold either a single keymap or an array of
keymaps.</p>
<p>When a keymap contains a <code>nofallthrough</code> property
set to <code>true</code>, keys matched against that map will be
ignored if they don't match any of the bindings in the map (no
further child maps will be tried). When
the <code>disableInput</code> property is set
to <code>true</code>, the default effect of inserting a character
will be suppressed when the keymap is active as the top-level
map.</p>
</section>
<<<<<<< HEAD
=======
<section id=commands>
<h2>Commands</h2>
<p>Commands are parameter-less actions that can be performed on an
editor. Their main use is for key bindings. Commands are defined by
adding properties to the <code>CodeMirror.commands</code> object.
A number of common commands are defined by the library itself,
most of them used by the default key bindings. The value of a
command property must be a function of one argument (an editor
instance).</p>
<p>Some of the commands below are referenced in the default
key map, but not defined by the core library. These are intended to
be defined by user code or addons.</p>
<p>Commands can also be run with
the <a href="#execCommand"><code>execCommand</code></a>
method.</p>
<dl>
<dt class=command id=command_selectAll><code><strong>selectAll</strong></code><span class=keybinding>Ctrl-A (PC), Cmd-A (Mac)</span></dt>
<dd>Select the whole content of the editor.</dd>
<dt class=command id=command_singleSelection><code><strong>singleSelection</strong></code><span class=keybinding>Esc</span></dt>
<dd>When multiple selections are present, this deselects all but
the primary selection.</dd>
<dt class=command id=command_killLine><code><strong>killLine</strong></code><span class=keybinding>Ctrl-K (Mac)</span></dt>
<dd>Emacs-style line killing. Deletes the part of the line after
the cursor. If that consists only of whitespace, the newline at
the end of the line is also deleted.</dd>
<dt class=command id=command_deleteLine><code><strong>deleteLine</strong></code><span class=keybinding>Ctrl-D (PC), Cmd-D (Mac)</span></dt>
<dd>Deletes the whole line under the cursor, including newline at the end.</dd>
<dt class=command id=command_delLineLeft><code><strong>delLineLeft</strong></code><span class=keybinding>Cmd-Backspace (Mac)</span></dt>
<dd>Delete the part of the line before the cursor.</dd>
<dt class=command id=command_undo><code><strong>undo</strong></code><span class=keybinding>Ctrl-Z (PC), Cmd-Z (Mac)</span></dt>
<dd>Undo the last change.</dd>
<dt class=command id=command_redo><code><strong>redo</strong></code><span class=keybinding>Ctrl-Y (PC), Shift-Cmd-Z (Mac), Cmd-Y (Mac)</span></dt>
<dd>Redo the last undone change.</dd>
<dt class=command id=command_undoSelection><code><strong>undoSelection</strong></code><span class=keybinding>Ctrl-U (PC), Cmd-U (Mac)</span></dt>
<dd>Undo the last change to the selection, or if there are no
selection-only changes at the top of the history, undo the last
change.</dd>
<dt class=command id=command_redoSelection><code><strong>redoSelection</strong></code><span class=keybinding>Alt-U (PC), Shift-Cmd-U (Mac)</span></dt>
<dd>Redo the last change to the selection, or the last text change if
no selection changes remain.</dd>
<dt class=command id=command_goDocStart><code><strong>goDocStart</strong></code><span class=keybinding>Ctrl-Up (PC), Cmd-Up (Mac)</span></dt>
<dd>Move the cursor to the start of the document.</dd>
<dt class=command id=command_goDocEnd><code><strong>goDocEnd</strong></code><span class=keybinding>Ctrl-Down (PC), Cmd-End (Mac), Cmd-Down (Mac)</span></dt>
<dd>Move the cursor to the end of the document.</dd>
<dt class=command id=command_goLineStart><code><strong>goLineStart</strong></code><span class=keybinding>Alt-Left (PC), Cmd-Left (Mac), Ctrl-A (Mac)</span></dt>
<dd>Move the cursor to the start of the line.</dd>
<dt class=command id=command_goLineStartSmart><code><strong>goLineStartSmart</strong></code><span class=keybinding>Home</span></dt>
<dd>Move to the start of the text on the line, or if we are
already there, to the actual start of the line (including
whitespace).</dd>
<dt class=command id=command_goLineEnd><code><strong>goLineEnd</strong></code><span class=keybinding>Alt-Right (PC), Cmd-Right (Mac), Ctrl-E (Mac)</span></dt>
<dd>Move the cursor to the end of the line.</dd>
<dt class=command id=command_goLineLeft><code><strong>goLineLeft</strong></code></dt>
<dd>Move the cursor to the left side of the visual line it is on. If
this line is wrapped, that may not be the start of the line.</dd>
<dt class=command id=command_goLineRight><code><strong>goLineRight</strong></code></dt>
<dd>Move the cursor to the right side of the visual line it is on.</dd>
<dt class=command id=command_goLineUp><code><strong>goLineUp</strong></code><span class=keybinding>Up, Ctrl-P (Mac)</span></dt>
<dd>Move the cursor up one line.</dd>
<dt class=command id=command_goLineDown><code><strong>goLineDown</strong></code><span class=keybinding>Down, Ctrl-N (Mac)</span></dt>
<dd>Move down one line.</dd>
<dt class=command id=command_goPageUp><code><strong>goPageUp</strong></code><span class=keybinding>PageUp, Shift-Ctrl-V (Mac)</span></dt>
<dd>Move the cursor up one screen, and scroll up by the same distance.</dd>
<dt class=command id=command_goPageDown><code><strong>goPageDown</strong></code><span class=keybinding>PageDown, Ctrl-V (Mac)</span></dt>
<dd>Move the cursor down one screen, and scroll down by the same distance.</dd>
<dt class=command id=command_goCharLeft><code><strong>goCharLeft</strong></code><span class=keybinding>Left, Ctrl-B (Mac)</span></dt>
<dd>Move the cursor one character left, going to the previous line
when hitting the start of line.</dd>
<dt class=command id=command_goCharRight><code><strong>goCharRight</strong></code><span class=keybinding>Right, Ctrl-F (Mac)</span></dt>
<dd>Move the cursor one character right, going to the next line
when hitting the end of line.</dd>
<dt class=command id=command_goColumnLeft><code><strong>goColumnLeft</strong></code></dt>
<dd>Move the cursor one character left, but don't cross line boundaries.</dd>
<dt class=command id=command_goColumnRight><code><strong>goColumnRight</strong></code></dt>
<dd>Move the cursor one character right, don't cross line boundaries.</dd>
<dt class=command id=command_goWordLeft><code><strong>goWordLeft</strong></code><span class=keybinding>Alt-B (Mac)</span></dt>
<dd>Move the cursor to the start of the previous word.</dd>
<dt class=command id=command_goWordRight><code><strong>goWordRight</strong></code><span class=keybinding>Alt-F (Mac)</span></dt>
<dd>Move the cursor to the end of the next word.</dd>
<dt class=command id=command_goGroupLeft><code><strong>goGroupLeft</strong></code><span class=keybinding>Ctrl-Left (PC), Alt-Left (Mac)</span></dt>
<dd>Move to the left of the group before the cursor. A group is
a stretch of word characters, a stretch of punctuation
characters, a newline, or a stretch of <em>more than one</em>
whitespace character.</dd>
<dt class=command id=command_goGroupRight><code><strong>goGroupRight</strong></code><span class=keybinding>Ctrl-Right (PC), Alt-Right (Mac)</span></dt>
<dd>Move to the right of the group after the cursor
(see <a href="#command_goGroupLeft">above</a>).</dd>
<dt class=command id=command_delCharBefore><code><strong>delCharBefore</strong></code><span class=keybinding>Shift-Backspace, Ctrl-H (Mac)</span></dt>
<dd>Delete the character before the cursor.</dd>
<dt class=command id=command_delCharAfter><code><strong>delCharAfter</strong></code><span class=keybinding>Delete, Ctrl-D (Mac)</span></dt>
<dd>Delete the character after the cursor.</dd>
<dt class=command id=command_delWordBefore><code><strong>delWordBefore</strong></code><span class=keybinding>Alt-Backspace (Mac)</span></dt>
<dd>Delete up to the start of the word before the cursor.</dd>
<dt class=command id=command_delWordAfter><code><strong>delWordAfter</strong></code><span class=keybinding>Alt-D (Mac)</span></dt>
<dd>Delete up to the end of the word after the cursor.</dd>
<dt class=command id=command_delGroupBefore><code><strong>delGroupBefore</strong></code><span class=keybinding>Ctrl-Backspace (PC), Alt-Backspace (Mac)</span></dt>
<dd>Delete to the left of the <a href="#command_goGroupLeft">group</a> before the cursor.</dd>
<dt class=command id=command_delGroupAfter><code><strong>delGroupAfter</strong></code><span class=keybinding>Ctrl-Delete (PC), Ctrl-Alt-Backspace (Mac), Alt-Delete (Mac)</span></dt>
<dd>Delete to the start of the <a href="#command_goGroupLeft">group</a> after the cursor.</dd>
<dt class=command id=command_indentAuto><code><strong>indentAuto</strong></code><span class=keybinding>Shift-Tab</span></dt>
<dd>Auto-indent the current line or selection.</dd>
<dt class=command id=command_indentMore><code><strong>indentMore</strong></code><span class=keybinding>Ctrl-] (PC), Cmd-] (Mac)</span></dt>
<dd>Indent the current line or selection by one <a href="#option_indentUnit">indent unit</a>.</dd>
<dt class=command id=command_indentLess><code><strong>indentLess</strong></code><span class=keybinding>Ctrl-[ (PC), Cmd-[ (Mac)</span></dt>
<dd>Dedent the current line or selection by one <a href="#option_indentUnit">indent unit</a>.</dd>
<dt class=command id=command_insertTab><code><strong>insertTab</strong></code></dt>
<dd>Insert a tab character at the cursor.</dd>
<dt class=command id=command_insertSoftTab><code><strong>insertSoftTab</strong></code></dt>
<dd>Insert the amount of spaces that match the width a tab at
the cursor position would have.</dd>
<dt class=command id=command_defaultTab><code><strong>defaultTab</strong></code><span class=keybinding>Tab</span></dt>
<dd>If something is selected, indent it by
one <a href="#option_indentUnit">indent unit</a>. If nothing is
selected, insert a tab character.</dd>
<dt class=command id=command_transposeChars><code><strong>transposeChars</strong></code><span class=keybinding>Ctrl-T (Mac)</span></dt>
<dd>Swap the characters before and after the cursor.</dd>
<dt class=command id=command_newlineAndIndent><code><strong>newlineAndIndent</strong></code><span class=keybinding>Enter</span></dt>
<dd>Insert a newline and auto-indent the new line.</dd>
<dt