js改变div的背景.IE6下无法显示.要把图的地址在网页上打上.才能显示那个图

function showImg(divID,str)
{
  
var url="/NormalImg.aspx?PictureProductID="+str;
var Normalimg =openUrl(url);
Normalimg = Normalimg.substring(0,Normalimg.indexOf('^')); 
url="/LargeImg.aspx?PictureProductID="+str;
var Largeimg =openUrl(url);
Largeimg = Largeimg.substring(0,Largeimg.indexOf('^'));
var div= document.getElementById(divID);div.style.background= "url("+Normalimg+") no-repeat";  }