<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>无标题文档</title>
<style>
li { height:30px; border-bottom:1px solid #333; }
</style>
<script>
window.onload = function (){
var oUl = document.getElementById('list');
var aLi = oUl.getElementsByTagName('li');
var arr = [ '今天', '明天', '后天' ];
var len = arr.length;
/*
aLi[0].onclick = function (){ alert(1); };
aLi[1].onclick = function (){ alert(1); };
aLi[2].onclick = function (){ alert(1); };
*/
// aLi.onclick = function (){ alert(1); };
for( var i=0; i<len; i++ ){
aLi[i].innerHTML = arr[i];
aLi[i].onclick = function (){
// alert(i); i => 3
};
}
};
</script>
</head>
<body>
<ul id="list">
<li></li>
<li></li>
<li></li>
</ul>
</body>
</html>
来源：https://www.cnblogs.com/tongguilin/p/12179102.html