modernizr
Version:
Modernizr is a JavaScript library that detects HTML5 and CSS3 features in the user’s browser.
33 lines (32 loc) • 866 B
JavaScript
/*!
{
"name": "ES5 Immutable Undefined",
"property": "es5undefined",
"notes": [{
"name": "ECMAScript 5.1 Language Specification",
"href": "http://www.ecma-international.org/ecma-262/5.1/"
}, {
"name": "original implementation of detect code",
"href": "http://kangax.github.io/es5-compat-table/"
}],
"authors": ["Ron Waldon (@jokeyrhyme)"],
"tags": ["es5"]
}
!*/
/* DOC
Check if browser prevents assignment to global `undefined` per ECMAScript 5.
*/
define(['Modernizr'], function(Modernizr) {
Modernizr.addTest('es5undefined', function() {
var result, originalUndefined;
try {
originalUndefined = window.undefined;
window.undefined = 12345;
result = typeof window.undefined === 'undefined';
window.undefined = originalUndefined;
} catch (e) {
return false;
}
return result;
});
});