<!DOCTYPE html>
<html>
<head>
问<meta charset="UTF-8">
<title></title>
<style type="text/css">
a{
width: 50px;
height: 50px;
background: red;
}
</style>
</head>
<body>
<script>
var number;
function clicke() {
var a = document.getElementById("mya");
a.style.cssText +="; display:block;width: 100%;height:200px;background: yellow;";
}
</script>
<a id="mya" href="#" onclick="clicke()">点击我答</a>
</body>
</html>
$("#mya").addClass("on");