原生javascript实现的一个简单动画

<code class="language-html"> 
 
 
<meta charset=" utf-8"> 

<title>javascript实现的简单动画</title>
<style type="text/css">
#mydiv
{
  width:50px;
  height:50px;
  background-color:green;
  position:absolute;
}
</style>
<script type="text/javascript"> 
window.onload=function()
{
  var mydiv=document.getElementById("mydiv");
  var start=document.getElementById("start");
  var stopmove=document.getElementById("stopmove");
  var x=0;
  var flag;
  function move()
  {
    x=x+1;
    mydiv.style.left=x+"px";
  }
  start.onclick=function()
  {
    clearInterval(flag);
    flag=setInterval(move,20);
  }
  stopmove.onclick=function()
  {
    clearInterval(flag);
  }
 
}
</script>

<input type="button" id="start" value="开始运动">
<input type="button" id="stopmove" value="停止运动">
<div id="mydiv"></div>

</code>