复制代码代码如下：
<html xmlns =“ http://www.w3.org/1999/xhtml”>
<头>
<meta http-equiv =“ content-type” content =“ text /html; charset = utf-8” />
<Title> JS </Title>
<脚本类型=“ text/javascript”>
window.onload = function（）
{
var oul = document.getElementById（'ul1'）;
var ali = ououl.getElementsbytagname（'li'）;
for（var i = 0; i <ali .length; i ++）
{
if（i％2 == 0）//
{
ali [i] .style.background ='red';
}
}
}
</script>
</script> </head>
<身体>
<ul id =“ ul1”>
<li> Webtall </li>
<li> Webtall </li>
<li> Webtall </li>
<li> Webtall </li>
<li> Webtall </li>
</ul>
</body>
</html>