帮我看看这个拖曳代码，怎么修改才能兼容ie7,8,9,我不知道是哪儿写错了，chrome和ff测试都能行，ie就是不能拖曳

window.onload = function()
{

var bar = document.getElementById('bar');
var box = document.getElementById("box");
bar.onmousedown = function(event)
{
  var event = event || window.event;
  // console.log(event.clientX);
   console.log(box.offsetTop);
  var disX = event.clientX - box.offsetLeft;//偏移量
  var disY= event.clientY - box.offsetTop;
  console.log(disY);

  document.onmousemove = function(event)
  {
      event = event || window.event;
      mouseMove(event,disX,disY);
  }
  document.onmouseup = function()
  {
      document.onmousemove = null;
      document.onmouseup = null;
  }
}    

}
function mouseMove(event,disX,disY)

{
   var box = document.getElementById('box');
   var event = event || window.event;
   var left = event.clientX - disX;
   var top = event.clientY - disY;
   winWidth = document.documentElement.clientWidth || document.body.clientWidth;
   winHeight = document.documentElement.clientHeight || document.body.clientHeight;
   maxW = winWidth - box.offsetWidth;
   maxH = winHeight - box.offsetHeight;
   if (left > maxW) 
       {
           left = maxW;
       }
       else if (left < 0) 
           {
               left = 0;
           }
       else if(top >maxH)
       {
           top = maxH;
       }
       else if(top < 0)
       {
     top = 0;
       }
   box.style.left = left +'px';
   box.style.top = top + 'px';
}

</script>

---

实在看不懂你要干什么

---

IE不兼容document.documentElement.clientWidth和document.documentElement.clientHeight,兼容IE应该使用document.body.clientWidth或document.body.clientHeight,兼容全部的写法如下：

var winWidth = document.documentElement.clientWidth || document.body.clientWidth;
var winHeight = document.documentElement.clientHeight || document.body.clientHeight;

从你的代码上看，你是通过拖动#bar来使#box跟着运动，看不到你的html结构，你具体的需求是什么？

---

你写的是一个拖拽，然后你要表达哪里不兼容IE还是出现什么问题？就一堆代码，不懂要干嘛。建议您可以把问题描述清楚，这样也方便人家回答。