function getFilePath(obj) 
    {  
      if(obj)  
      {  
        if (window.navigator.userAgent.indexOf("MSIE")>=1)  
        {  
          obj.select();  
         return document.selection.createRange().text;  
       }  
    
       else if(window.navigator.userAgent.indexOf("Firefox")>=1)  
       {  
         if(obj.files)  
         {  
    
           return obj.files.item(0).getAsDataURL();  
         }  
         return obj.value;  
       }  
       return obj.value;  
     }   
  } 
  /**
   * @obj			file表单对象
   * @previewId		预览图id(见意用div)
   * @width			预览图宽
   * @height		预览图高
   */
  function createPreview(obj,previewId,width,height){
  	var newPreview = document.getElementById(previewId);
  	if(window.ActiveXObject){
		newPreview.innerHTML='';
		newPreview.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=scale)";
		newPreview.filters.item("DXImageTransform.Microsoft.AlphaImageLoader").src = getFilePath(obj);
		newPreview.style.width = width+"px";
		newPreview.style.height = height+"px";
	}else{
		//$("#preview").attr("src",getPath(obj));
		newPreview.innerHTML='<img width=100 height=100 src='+getFilePath(obj)+' />';
	}
  }