例子
<!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>
<style type="text/css">
.item{ width:200px; height:200px; background-color:#60F; float:left; margin:2px;}
</style>
</head>
<body>
<div class="item" onclick="sel(this)"></div>
<div class="item" onclick="sel(this)"></div>
<div class="item" onclick="sel(this)"></div>
<div class="item" onclick="sel(this)"></div>
<div class="item" onclick="sel(this)"></div>
<div class="item" onclick="sel(this)"></div>
<div class="item" onclick="sel(this)"></div>
<div class="item" onclick="sel(this)"></div>
<div class="item" onclick="sel(this)"></div>
<div class="item" onclick="sel(this)"></div>
<div class="item" onclick="sel(this)"></div>
<div class="item" onclick="sel(this)"></div>
</body>
<script type="text/javascript">
function sel(a){
//让所有元素变为出事颜色
var sy = document.getElementsByClassName("item")
for(var i=0;i<sy.length;i++){
sy[i].style.backgroundColor ="blue";
}
//让该元素变选中
a.style.backgroundColor="red";
}
</script>
</html>
