if (document.images)
   {
     pic1on= new Image(166,32);
     pic1on.src="images/dworks_button01_on.gif";  

     pic1off= new Image(166,32);
     pic1off.src="images/dworks_button01_off.gif";
     
     pic2on= new Image(166,32);
     pic2on.src="images/dworks_button02_on.gif";  

     pic2off= new Image(166,32);
     pic2off.src="images/dworks_button02_off.gif";
     
     pic3on= new Image(166,32);
     pic3on.src="images/dworks_button03_on.gif";  

     pic3off= new Image(166,32);
     pic3off.src="images/dworks_button03_off.gif";
     
   }

function lightup(imgName)
 {
   if (document.images)
    {
      imgOn=eval(imgName + "on.src");
      document[imgName].src= imgOn;
    }
 }

function turnoff(imgName)
 {
   if (document.images)
    {
      imgOff=eval(imgName + "off.src");
      document[imgName].src= imgOff;
    }
 }