gif动态效果

代码段
<head lang="en">
<meta charset="UTF-8">
<title></title>
<script src = jquery1.js></script>
<style>
.blue{
height: 50px;
width: 40px;
background-color: blue;
border-radius:20px 20px 2px 2px ;
}
.red{
height: 50px;
width: 40px;
background-color: red;
border-radius:20px 20px 2px 2px ;
}
</style>
</head>
<body>
<div class="blue"></div><br/>
<input type="button" id="open" value="开启"/>
<input type="button" id="close" value="关闭"/>
<script type="text/javascript">
var interval ;
function open(){
if(interval != undefined){
alert("已经启动!")
}else{
interval = setInterval(function(){
$("div").toggleClass("red");
},100);
}
}
function close(){
clearInterval(interval);
interval = undefined;
}
$(function(){
$("#close").click(function(){
close()
});
$("#open").click(function(){
open();
});
});
</script>
</body>