<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title></title>
<script type="text/javascript">
//this是表示当前监听事件这个对象，event.srcElement是引发事件的对象
function btnClick() {//相应事件函数中不能用this来获取事件对象
alert(this.value);
}
function btnClick2(btn) {//将this作为参数传过来 alert(btn.value);
}
</script>
</head>
<body>
<input type="button" value="click1" onclick="alert(event.srcElement.value)" />
<input type="button" value="click2" onclick="alert(this.value)" />
<input type="button" value="click3" onclick="btnClick()" />
<input type="button" value="click4" onclick="btnClick2(this)" />
</body>
</html>