var Event = {
		add: function(obj,type,fn) {
			if (obj.attachEvent) {
				obj['e'+type+fn] = fn;
				obj[type+fn] = function() { obj['e'+type+fn](window.event); }
				obj.attachEvent('on'+type,obj[type+fn]);
			} else
			obj.addEventListener(type,fn,false);
		},
		remove: function(obj,type,fn) {
			if (obj.detachEvent) {
				obj.detachEvent('on'+type,obj[type+fn]);
				obj[type+fn] = null;
			} else
			obj.removeEventListener(type,fn,false);
		}
	}
	
	function $() {
		var elements = new Array();
		for (var i=0;i<arguments.length;i++) {
			var element = arguments[i];
			if (typeof element == 'string') element = document.getElementById(element);
			if (arguments.length == 1) return element;
			elements.push(element);
		}
		return elements;
	}
	
	String.prototype.trim = function() {
		return this.replace(/^\s+|\s+$/,"");
	}
	
	function addClassName(el,className) {
		removeClassName(el,className);
		el.className = (el.className + " " + className).trim();
	}
	
	function removeClassName(el,className) {
		el.className = el.className.replace(className,"").trim();
	}
	
	var ZebraTable = {
		bgcolor: '',
		classname: '',
		stripe: function(el) {
			if (!$(el)) return;
			var rows = $(el).getElementsByTagName('tr');
			for (var i=1,len=rows.length;i<len;i++) {
				if (i % 2 == 0) rows[i].className = 'alt';
				Event.add(rows[i],'mouseover',function() { ZebraTable.mouseover(this); });
				Event.add(rows[i],'mouseout',function() { ZebraTable.mouseout(this); });
			}
		},
		mouseover: function(row) {
			this.bgcolor = row.style.backgroundColor;
			this.classname = row.className;
			addClassName(row,'over');
		},
		mouseout: function(row) {
			removeClassName(row,'over');
			addClassName(row,this.classname);
			row.style.backgroundColor = this.bgcolor;
		}
	}
	
	window.onload = function() {
		ZebraTable.stripe('t1');
		ZebraTable.stripe('t2');
	}