/*
function $(id) {
	var elm;
	if(elm = document.getElementById(id)) return elm;
	return null;
}
*/

function getElementsByClassName(elm, tag, cl) {
	var retnode = [];
	var myclass = new RegExp('\\b'+cl+'\\b');
	var elem = elm.getElementsByTagName(tag);
	for (var i = 0; i < elem.length; i++) {
		var classes = elem[i].className;
		if (myclass.test(classes)) retnode.push(elem[i]);
	}
	
	return retnode;
}

function addEvent(obj,evt,fn) {
	if (obj.addEventListener)
		obj.addEventListener(evt,fn,false);
	else if (obj.attachEvent)
		obj.attachEvent('on'+evt,fn);
}

function removeEvent(obj,evt,fn) {
	if (obj.removeEventListener)
		obj.removeEventListener(evt,fn,false);
	else if (obj.detachEvent)
		obj.detachEvent('on'+evt,fn);
}

function addClassName(obj, cName) {
	removeClassName(obj, cName);
	if(obj.className != "") obj.className += " " + cName;
	else obj.className = cName;
}

function removeClassName(obj, cName) {
	if(obj.className != "") {
		var cArr = obj.className.split(" ");
		for(var i = cArr.length-1; i >= 0; i--) {
			if(cArr[i] == cName) cArr.splice(i, 1);
		}
		obj.className = cArr.join(" ");
	}
}