get-elements-by-classname.js

function getElementsByClassName(node,classname) {
	if (node.getElementsByClassName) {
		return node.getElementsByClassName(classname);
	} else {
		document.getElementsByClassName = function( className, nodeName ) {
 	 		var result = [], tag = nodeName||'*', node, seek, i;
	  		if( document.evaluate ) {
				seek = '//'+ tag +'[@class="'+ className +'"]';
				seek = document.evaluate( seek, document, null, 0, null );
				while((node = seek.iterateNext())) {
 					result.push( node );
				}
			} else {
    				var rightClass = new RegExp( '(^| )'+ className +'( |$)' );
    				seek = document.getElementsByTagName( tag );
    				for (i=0; i<seek.length; i++) {
					if(rightClass.test((node = seek[i]).className)) {
						result.push(seek[i]);
					}
				}
  			}
			return result;
		};
	}
}