<html>
<body>
<div id="div1">点我绑定事件</div>
<script>
var addEvent = function( elem, type, handler ){
//重写addEvent的好处是下一次调用时不会再走if判断，提高了一部分性能
if ( window.addEventListener ){
addEvent = function( elem, type, handler ){
elem.addEventListener( type, handler, false );
}
}else if ( window.attachEvent ){
addEvent = function( elem, type, handler ){
elem.attachEvent( 'on' + type, handler );
}
}
addEvent( elem, type, handler );
};
var div = document.getElementById( 'div1' );
addEvent( div, 'click', function(){
alert (1);
});
addEvent( div, 'click', function(){
alert (2);
});
</script>
</body>
</html>
