if (document.images) {
 nav1_on =new Image();  nav1_on.src ="images/nav01-on.gif"; 
 nav1_off=new Image();  nav1_off.src="images/nav01.gif"; 

 nav2_on =new Image();  nav2_on.src ="images/nav02-on.gif"; 
 nav2_off=new Image();  nav2_off.src="images/nav02.gif"; 

 nav3_on =new Image();  nav3_on.src ="images/nav03-on.gif"; 
 nav3_off=new Image();  nav3_off.src="images/nav03.gif"; 

 nav4_on =new Image();  nav4_on.src ="images/nav04-on.gif"; 
 nav4_off=new Image();  nav4_off.src="images/nav04.gif"; 

 nav5_on =new Image();  nav5_on.src ="images/nav05-on.gif"; 
 nav5_off=new Image();  nav5_off.src="images/nav05.gif"; 

 nav6_on =new Image();  nav6_on.src ="images/nav06-on.gif"; 
 nav6_off=new Image();  nav6_off.src="images/nav06.gif"; 

 nav7_on =new Image();  nav7_on.src ="images/nav07-on.gif"; 
 nav7_off=new Image();  nav7_off.src="images/nav07.gif"; 

 nav8_on =new Image();  nav8_on.src ="images/nav08-on.gif"; 
 nav8_off=new Image();  nav8_off.src="images/nav08.gif"; 

 nav9_on =new Image();  nav9_on.src ="images/nav09-on.gif"; 
 nav9_off=new Image();  nav9_off.src="images/nav09.gif"; 

 nav10_on =new Image();  nav10_on.src ="images/nav10-on.gif"; 
 nav10_off=new Image();  nav10_off.src="images/nav10.gif"; 

}

function imgOn(i) {
 if (document.images) 
  eval('document.nav'+i+'.src = nav'+i+'_on.src');
}

function imgOff(i) {
 if (document.images) 
  eval('document.nav'+i+'.src = nav'+i+'_off.src');
}