a1=new Image(45,45)
	a1.src="/images/nav-off_01.gif"
	a2=new Image(45,45)
	a2.src="/images/nav-on_01.gif"
	
	b1=new Image(45,45)
	b1.src="/images/nav-off_02.gif"
	b2=new Image(45,45)
	b2.src="/images/nav-on_02.gif"

	c1=new Image(45,45)
	c1.src="/images/nav-off_03.gif"
	c2=new Image(45,45)
	c2.src="/images/nav-on_03.gif"
	
	d1=new Image(45,45)
	d1.src="/images/nav-off_04.gif"
	d2=new Image(45,45)
	d2.src="/images/nav-on_04.gif"
	
	function filter(imagename,objectsrc){
	if (document.images)
	document.images[imagename].src=eval(objectsrc+".src")
	}