getElementsByClassName() in IE8
Internet Explorer 8 (IE8) web browser does not support the
getElementsByClassName() DOM method, so when trying to call the method, IE8 shows “Object doesn't support this property or method” error message in console.
However IE8 supports the
querySelectorAll() method that allows to achieve the same goal without using any JS libraries:
var elems = document.getElementsByClassName('foo bar'); // IE9+
var elems = document.querySelectorAll('.foo.bar'); // IE8
In the example above, both calls select elements that have both
getElementsByClassName() method is intended for selecting elements by one or multiple classes, while
querySelectorAll() searches elements that match a selector.
In browsers that support both methods, using
getElementsByClassName() to select elements by classes may be preferrable due to its potentially higher performance thanks to that there is no need for full-scale parsing of selector that may contain by far not only classes.
You may also be interested in
matchesSelector() for IE8.