jQuery 开始动画，停止动画

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>效果2</title>
    <script src="js/jquery-1.7.1.min.js"></script>
</head>
<style>
    .fff{
        background: #fff;
        border: 1px solid #000;
    }
    .head{line-height: 30px;background: #999;}
    .arrow{width: 20px;height: 20px;background: red;display: block;float: right;}
    .div1{
        width: 100%;
        height: 50px;
        background: red;
    }
    .ani-1{
        width: 50px;
        height: 50px;
        background: red;
    }
</style>
<script>
    $(document).ready(function(){
     $(".arrow").click(function(){
        $("#div1").slideToggle();
    });

     $("#go").click(function(){
         $("#anA").animate({
             width:"400px",
             height:"400px",
             fontSize:"18px",
             marginLeft:"30px"
         },5000)
     })
      $("#sttop").click(function(){
         $("#anA").stop()
     })

      jQuery.fx.interval = 100;

$("input").click(function(){
  $("div").toggle( 3000 );
});

});
</script>
<body>
    <div class="head">我是大标题  <a class="arrow" onclick="btn_click()"></a></div>

<div id="div1" class="div1"></div>

<button id="go">开始动画</button> <button id="sttop">停止动画</button>

<div class="ani-1" id="anA">哈哈哈，你来打我啊</div>
<p><input type="button" value="Run"/></p>
<div></div>

</body>
</html>