javascript document.getElementsByClassName compatibility with IE

Question

What is the best method to retrieve an array of elements that have a certain class?

I would use document.getElementsByClassName but IE does not support it.

Answer 1

It's not a method of document:

function getElementsByClassName(node, classname) {
    var a = [];
    var re = new RegExp('(^| )'+classname+'( |$)');
    var els = node.getElementsByTagName("*");
    for(var i=0,j=els.length; i