一个树形菜单,每一项对应一个独立的ID,我要在选择一项后得到其ID,该怎么办?

<html>
<head>
<title></title>
<meta name="Generator" content="EditPlus">
<meta name="Author" content="JnKc">
<meta name="Keywords" content="">
</head>
<body onClick="(event.srcElement.id!='')?alert(event.srcElement.id):''">
<div id="div1">111111</div>
<div id="div2">222222</div>
<div id="div3">333333</div>
<div id="div4">444444</div>
<div id="div5">555555</div>
<div id="div6">666666</div>
<div id="div7">777777</div>
</body>
</html>