javascript注册事件的四种方式

• <button onclick="alert('aaa')"></button>
• element.onclick=function(){}
• element.onclick=new Function()
• element.attachEvent("onclick",function(){})

给oTarget的sEventType事件注册一个fnHandler的方法

	function addEventHandler(oTarget, sEventType, fnHandler) {
		if (oTarget.addEventListener)
		{
			oTarget.addEventListener(sEventType, fnHandler, false);
		} else if (oTarget.attchEvent)
		{
			oTarget.attachEvent("on" + sEventType, fnHandler);
		} else {
			oTarget("on" + sEventType) = fnHandler;
		}
	};