js 键盘移动div、img对象

 <html>

 <script type="text/javascript">

  var EXtype="";

  var len=5; //步长

  var level=1;//变速倍数

  var sprite;//div img 或者sprite，移动目标

   //检测浏览器版本 函数

  function getExplorerVersion(){

     var Sys = {};//js 所谓的面向对象 对象

         var ua = navigator.userAgent.toLowerCase();

         if (window.ActiveXObject)

             Sys.ie = ua.match(/msie ([\d.]+)/)[1];

         else if (document.getBoxObjectFor)

             Sys.firefox = ua.match(/firefox\/([\d.]+)/)[1];

         else if (window.MessageEvent && !document.getBoxObjectFor)

             Sys.chrome = ua.match(/chrome\/([\d.]+)/)[1];

         else if (window.opera)

             Sys.opera = ua.match(/opera.([\d.]+)/)[1];

         else if (window.openDatabase)

             Sys.safari = ua.match(/version\/([\d.]+)/)[1];

         if(Sys.ie){ document.write('IE: '+Sys.ie);

         EXtype="IE";

          }

         if(Sys.firefox){ document.write('Firefox: '+Sys.firefox);

         EXtype="Firefox";

         }

         if(Sys.chrome){ document.write('Chrome: '+Sys.chrome);

         EXtype="Chrome";

         }

         if(Sys.opera){ document.write('Opera: '+Sys.opera);

         EXtype="Opera";

         }

         if(Sys.safari){ document.write('Safari: '+Sys.safari);

         EXtype="Safari";

         }

         return EXtype;

  }

  //检测浏览器版本

  getExplorerVersion();

 function onkeyEvent(e)

 {

    var kc="";

    if(EXtype=="IE"){    kc=window.event.keyCode; }

    else

    if(EXtype=="Chrome"){ kc= event.which; }

    step(kc);

  }

 //move

 function step(seq)

 {

     switch(seq)

     {

      case 37:

       sprite.style.left = (parseInt(sprite.style.left) - speed(len)) + "px"; //left

       break;

      case 38:

       sprite.style.top = (parseInt(sprite.style.top) - speed(len)) + "px"; //up

       break;

      case 39:

        sprite.style.left = (parseInt(sprite.style.left) + speed(len)) + "px"; //right

       break;

      case 40:

       sprite.style.top = (parseInt(sprite.style.top) + speed(len)) + "px"; //down

       break;

     }

 }

 //变速

 function speed(level)

 {

  var steplenvar=len*level;

   return steplenvar;

 }

 //监听

 document.onkeydown =onkeyEvent;

 function init(){

   sprite=document.getElementById("sprite");

 }

 //更换移动对象

 function clicksprite(e)

 {

    var choosediv=e;

    sprite=document.getElementById(choosediv);

 }

 </script>

 <body onload="init()">

          <div id="sprite" style="position:absolute; left:0px;top:0px;width:200px;height:100px;color:#000000;background-color:#ffff99;" onclick="clicksprite(this.id)"> </div>

           <div id="sprite1" style="position:absolute; left:100px;top:100px;width:200px;height:100px;color:#000000;background-color:#000fff;" onclick="clicksprite(this.id)"> </div>

 </body>

 </html>