javascript document.getElementsByClassName compatibility with IE

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<j; i++) if(re.test(els[i].className))a.push(els[i]); return a; } tabs = getElementsByClassName(document.body,’tab’); // no document