<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>小火箭發(fā)射</title>
  <style type="text/css">
    *{
      margin: 0px;
      padding: 0px;
    }
    .big{
      width: 500px;
      height: 600px;
      border: 1px solid #16283B;
      float: left;
      position: relative;
      background-color: #16283B;
    }
    .btm{
      height: 40px;
      width: 100px;
      background-color: royalblue;
      cursor: pointer;
      border: 1px solid blue;
      float: left;
      position: relative;
      top: 560px;
      left: 40px;
    }
    .btm span{
      line-height: 40px;
      width: 100px;
      display: block;
      text-align: center;
    }
    .bt_stop{
      height: 40px;
      width: 100px;
      background-color: royalblue;
      cursor: pointer;
      border: 1px solid blue;
      float: left;
      position: relative;
      top: 500px;
      left: -60px;
    }
    .bt_stop span{
      line-height: 40px;
      width: 100px;
      display: block;
      text-align: center;
    }
    .rocket{
      position: absolute;
      bottom: 18px;
      left: 180px;
    }
  </style>
  <script type="text/javascript">
    // alert("is work!");
    //任務(wù)1 火箭起飛
    //任務(wù)2 火箭懸停
    var start;
    function $(id) {
      return document.getElementById(id);
    }
    function fly() {
      start=self.setInterval("fly_do()",10);
    }
    function start_send() {
      alert('start');
      fly();
    }
    function stop() {
      //alert('stop');
      window.clearInterval(start);
    }
    function getBottom(rocket) {
      var bottomf = rocket.style.bottom;
      bottomf = parseInt(bottomf);
      if (!bottomf){
        bottomf=18;
      }
      bottomf++;
      return bottomf;
    }
    function fly_do() {
      //alert("this is fly");
      //通過不斷改變r(jià)ocket里面的css屬性bottom
      //獲取rocket對象
      var rocket=$("yingshanhao");
      var bottomf=getBottom(rocket);
      //改變屬性
      rocket.style.bottom=bottomf+"px";
      //慢慢飛起來
      //js的時(shí)間函數(shù)
    }
  </script>
</head>
<body>
    <div class="big">
      <div class="rocket" id="yingshanhao">
        <img src="images/rocket1.jpg" style="width: 25%;height:25%;position: relative;left: 40px;bottom: -20px;" >
        </div>
      </div>
      <div class="btm" onmouseover="javascript:stop();" onmouseout="javascript:start_send();">
        <span>懸停按鈕</span>
      </div>
      <div class="bt_stop" onclick="javascript:fly();">
        <span>發(fā)射按鈕</span>
      </div>
    </div>
</body>
</html>

感興趣的朋友可以使用在線HTML/CSS/JavaScript代碼運(yùn)行工具：http://tools.jb51.net/code/HtmlJsRun測試一下運(yùn)行效果。