JS获取class的方法一：
普通版：
<script type="text/javascript">
function getByClass(oParent, sClass)
{
var aEle=oParent.getElementsByTagName('*');
var aResult=[];
var i=0;
for(i=0;i<aEle.length;i++)
{
if(aEle[i].className==sClass)
{
aResult.push(aEle[i]);
}
}
return aResult;
}
</script>
JS获取class的方法二：
完美版：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<script>
function getByClass(oParent, sClass)
{
var aEle=oParent.getElementsByTagName('*');
var aResult=[];
var re=new RegExp('\b'+sClass+'\b', 'i');
var i=0;
for(i=0;i<aEle.length;i++)
{
//if(aEle[i].className==sClass)
//if(aEle[i].className.search(sClass)!=-1)
if(re.test(aEle[i].className))
{
aResult.push(aEle[i]);
}
}
return aResult;
}
window.onload=function ()
{
var oUl=document.getElementById('ul1');
var aBox=getByClass(oUl, 'box');
var i=0;
for(i=0;i<aBox.length;i++)
{
aBox[i].style.background='red';
}
};
</script>
</head>
<body>
<ul id="ul1">
<li></li>
<li class="box active"></li>
<li class="box"></li>
<li></li>
<li></li>
<li class="box"></li>
</ul>
</body>
</html>