function Viewer(Name, strFile, imgWidth, imgHeight)
    {
       var lLeft, lTop;
       if (navigator.appName == 'Microsoft Internet Explorer')
       {
          imgWidth = imgWidth + 22;
          imgHeight = imgHeight + 28;
       }
       lLeft = (screen.availWidth - imgWidth) / 2;
       lTop = (screen.availHeight - imgHeight) / 2;
       window.open(strFile,Name,'height=' + imgHeight + ',width=' + imgWidth + ',left=' + lLeft + ',top=' + lTop);										
      
  }