google-closure-library
Version:
Google's common JavaScript library
83 lines (71 loc) • 2.3 kB
JavaScript
/**
* @license
* Copyright The Closure Library Authors.
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @fileoverview Helper object used by modal elements to control aria
* visibility of the rest of the page.
*/
goog.provide('goog.ui.ModalAriaVisibilityHelper');
goog.require('goog.a11y.aria');
goog.require('goog.a11y.aria.State');
goog.requireType('goog.dom.DomHelper');
/**
* Helper object to control aria visibility of the rest of the page (background)
* for a given element. Example usage is to restrict screenreader focus to
* a modal popup while it is visible.
*
* WARNING: This will work only if the element is rendered directly in the
* 'body' element.
*
* @param {!Element} element The given element.
* @param {!goog.dom.DomHelper} domHelper DomHelper for the page.
* @constructor
*/
goog.ui.ModalAriaVisibilityHelper = function(element, domHelper) {
'use strict';
/**
* @private {!Element}
*/
this.element_ = element;
/**
* @private {!goog.dom.DomHelper}
*/
this.dom_ = domHelper;
};
/**
* The elements set to aria-hidden when the popup was made visible.
* @type {Array<!Element>}
* @private
*/
goog.ui.ModalAriaVisibilityHelper.prototype.hiddenElements_;
/**
* Sets aria-hidden on the rest of the page to restrict screen reader focus.
* Top-level elements with an explicit aria-hidden state are not altered.
* @param {boolean} hide Whether to hide or show the rest of the page.
*/
goog.ui.ModalAriaVisibilityHelper.prototype.setBackgroundVisibility = function(
hide) {
'use strict';
if (hide) {
if (!this.hiddenElements_) {
this.hiddenElements_ = [];
}
var topLevelChildren = this.dom_.getChildren(this.dom_.getDocument().body);
for (var i = 0; i < topLevelChildren.length; i++) {
var child = topLevelChildren[i];
if (child != this.element_ &&
!goog.a11y.aria.getState(child, goog.a11y.aria.State.HIDDEN)) {
goog.a11y.aria.setState(child, goog.a11y.aria.State.HIDDEN, true);
this.hiddenElements_.push(child);
}
}
} else if (this.hiddenElements_) {
for (var i = 0; i < this.hiddenElements_.length; i++) {
goog.a11y.aria.removeState(
this.hiddenElements_[i], goog.a11y.aria.State.HIDDEN);
}
this.hiddenElements_ = null;
}
};