JS 方法注入 attachEvent

写法1：

<html>
<head>
<title></title>
<script language="javascript" type="text/javascript"> 
    function dbClick() {
        alert(2);
    }
    function attClick() {
        alert(1);
    }
    function load() {
        var b = document.getElementById('mytd');
        b.attachEvent("onclick", attClick);
    }
</script>
</head>

<body id="mybody" onload="load();"  >
   
    <table><tr><td ><a  id="mytd" onclick="javascript:dbClick();">hello world!</a>
    
    </td></tr></table>
</body>
</html>

写法2：

<html>
<head>
<title></title>
<script language="javascript" type="text/javascript">

    window.attachEvent("onload", load);
    
    function dbClick() {
        alert(2);
    }
    function attClick() {
        alert(1);
    }
    function load() {
        var b = document.getElementById('mytd');
        b.attachEvent("onclick", attClick);
    }
</script>
</head>

<body id="mybody"  >
   
    <table><tr><td ><a  id="mytd" onclick="javascript:dbClick();">hello world!</a>
    
    </td></tr></table>
</body>
</html>

attachEvent的事件处理函数执行顺序

<script>
window.attachEvent("onload",function(){alert('a')});
window.attachEvent("onload",function(){alert('b')});
window.attachEvent("onload",function(){alert('c')});
</script>
<body onload=alert('x')>
</body>

下面这段代码触发是在 <body onload=alert('x')> 之后才触发的。

window.attachEvent("onload",function(){alert('a')});
window.attachEvent("onload",function(){alert('b')});
window.attachEvent("onload",function(){alert('c')});