if (document.images)
   {
     pic1on= new Image(100,25);
     pic1on.src="images/homebuttondown.jpg";

     pic2on= new Image(100,25);
     pic2on.src="images/biobuttondown.jpg";

     pic3on= new Image(100,25);
     pic3on.src="images/gallerybuttondown.jpg";

     pic4on= new Image(100,25);
     pic4on.src="images/testbuttondown.jpg";

     pic5on= new Image(100,25);
     pic5on.src="images/contactbuttondown.jpg";

     pic1off= new Image(100,25);
     pic1off.src="images/homebuttonnormal.jpg";

     pic2off= new Image(100,25);
     pic2off.src="images/biobuttonnormal.jpg";

     pic3off= new Image(100,25);
     pic3off.src="images/gallerybuttonnormal.jpg";

     pic4off= new Image(100,25);
     pic4off.src="images/testbuttonnormal.jpg";

     pic5off= new Image(100,25);
     pic5off.src="images/contactbuttonnormal.jpg";

   }

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;
    }
 }

 function disableselect(e){
 return false
 }

 function reEnable(){
 return true
 }

 //if IE4+
 document.onselectstart=new Function ("return false")
 document.oncontextmenu=new Function ("return false")
 //if NS6
 if (window.sidebar){
 document.onmousedown=disableselect
 document.onclick=reEnable
}