a1=new Image()
a1.src="nav1_off.gif"
a2=new Image()
a2.src="nav1_on.gif"
b1=new Image()
b1.src="nav2_off.gif"
b2=new Image()
b2.src="nav2_on.gif"
c1=new Image()
c1.src="nav3_off.gif"
c2=new Image()
c2.src="nav3_on.gif"
d1=new Image()
d1.src="nav4_off.gif"
d2=new Image()
d2.src="nav4_on.gif"
<!--
function filter(imagename,objectsrc){
if (document.images)
document.images[imagename].src=eval(objectsrc+".src")
}
function select_url(x)	{
location = x;
}