动态添加事件失败
var   fileuploadNum=1;
var   labelNum=1;
function   ul1Add()
{
fileuploadNum++;
labelNum++;
var   li=document.createElement( "li ");

var   fileupload=document.createElement( "input ");
var   label=document.createElement( "span ");


fileupload.setAttribute( "type ", "file ");
fileupload.setAttribute( "onmousedown ", "return   false; ");
fileupload.setAttribute( "onkeydown ", "return   false; ");

fileupload.id= "FileUpload "+fileuploadNum;
li.innerHTML= " <span> 产品快照 "+labelNum+ " </span> ";
li.appendChild(fileupload);
ul1.appendChild(li);


}
  <input   type= "file "   id= "FileUpload1 "   onkeydown   = "return   false; "     onmousedown= "return   false; "/>
<ul   id= "ul1 "> </ul>


在页面上我已经有一个file   控件名为FileUpload1~至于后面的那个事件我是实现用户不能输入或者修改~只能是选择
但是就不知道为什么这段代码所动态生成的file   控件的事件都失效

------解决方案--------------------
fileupload.setAttribute( "onmousedown ", "return false; ");
fileupload.setAttribute( "onkeydown ", "return false; ");

up

fileupload.onmousedown = function () { return false; };
fileupload.onkeydown= function () { return false; };
------解决方案--------------------
那个onmousedown 和 onkeydown 方法，必须触发一个函数，
所以必须要那样滴。而不是给定 具体值。。
------解决方案--------------------
fileupload.setAttribute( "onmousedown ", "return false; ");
fileupload.setAttribute( "onkeydown ", "return false; ");

在IE下是无效的……
在FF下好像有用……