if (/MSIE (\d+\.\d+);/.test(navigator.userAgent)){ //test for MSIE x.x;
var ieversion=new Number(RegExp.$1) // capture x.x portion and store as a number
if (ieversion<=6)
 document.write("<style type=\"text/css\">body{background-image:url(images/vista_bg2.gif);background-repeat: repeat-x;text-align: center;}</style>");
 else if (ieversion>=7)
  document.write("<style type=\"text/css\">body{background-image:url(images/vista_bg.gif);background-repeat: repeat-x;text-align: center;}</style>");
 
}
else
 document.write("<style type=\"text/css\">body{background-image:url(images/vista_bg.gif);background-repeat: repeat-x;text-align: center;}</style>");