浏览本地图片兼容firefox，ie6，ie7。。。

<script language="javascript">
     var isIE = false;
     var isFF = false;
     var isSa = false;
     if((navigator.userAgent.indexOf("MSIE")>0) && (parseInt(navigator.appVersion) >=4))isIE = true;
     if(navigator.userAgent.indexOf("Firefox")>0)isFF = true;
     if(navigator.userAgent.indexOf("Safari")>0)isSa = true;
    
      function fileChange(obj)
      {
         if(isIE)
         {
            var url = obj.value;
            url = "file:///" + url.replace("\\",'/');
                       
         }
         else if(isFF)
         {
             var url = obj.files.item(0).getAsDataURL();
            
         }
         document.getElementById("ImageFile").src= url;
      }
    
    </script><asp:FileUpload id=FileUpload1 onchange="fileChange(this);" runat="server"></asp:FileUpload><asp:Image id=ImageFile runat="server"></asp:Image>