Do we have getElementsByClassName in javascript?

Question

Just like in jQuery we can use $(\".classname\"), is there a similar thing in javascript as well? Or if we don\'t have such method then how can i implement that.
Accordi

Answer 1

Another good implementation of getElementsByClassName

Mixes an XPath and DOM implementation; using XPath wherever possible.

if (!('getElementsByClassName' in document)) {
    document.getElementsByClassName = function(className, parentElement) {
        if (Prototype.BrowserFeatures.XPath) {
            var q = ".//*[contains(concat(' ', @class, ' '), ' " + className + " ')]";
            return document._getElementsByXPath(q, parentElement);
        } else {
            var children = ($(parentElement) || document.body).getElementsByTagName('*');
            var elements = [],
                child;
            for (var i = 0, length = children.length; i < length; i++) {
                child = children[i];
                if (Element.hasClassName(child, className)) elements.push(Element.extend(child));
            }
            return elements;
        }
    };
}​

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P.S: Posting it here because I guess its faster than bobince answer. No offense :)
Got this from John Resig's getElementsByClassName Speed Comparison