if (document.images){
	home_off=new Image
	home_on=new Image
	introduction_off=new Image
	introduction_on=new Image
	tour_off=new Image
	tour_on=new Image
	checklist_off=new Image
	checklist_on=new Image
	colophon_off=new Image
	colophon_on=new Image
	themes_on=new Image
	firstrecords_on=new Image
	spanish_on=new Image
	goldrush_on=new Image
	vanguard_on=new Image
	inthearena_on=new Image
	scientific_on=new Image
	captivity_on=new Image
	grizzlyadams_on=new Image
	mascot_on=new Image
	emblem_on=new Image
		
	home_off.src="images/home_off.gif"
	home_on.src="images/home_on.gif"
	introduction_off.src="images/introduction_off.gif"
	introduction_on.src="images/introduction_on.gif"
	tour_off.src="images/tour_off.gif"
	tour_on.src="images/tour_on.gif"
	checklist_off.src="images/checklist_off.gif"
	checklist_on.src="images/checklist_on.gif"
	colophon_off.src="images/colophon_off.gif"
	colophon_on.src="images/colophon_on.gif"
	themes_on.src="images/themes_text.gif"
	firstrecords_on.src="images/firstrecords_text.gif"
	spanish_on.src="images/spanish_text.gif"
	goldrush_on.src="images/goldrush_text.gif"
	vanguard_on.src="images/vanguard_text.gif"
	inthearena_on.src="images/inthearena_text.gif"
	scientific_on.src="images/scientific_text.gif"
	captivity_on.src="images/captivity_text.gif"
	grizzlyadams_on.src="images/grizzlyadams_text.gif"
	mascot_on.src="images/mascot_text.gif"
	emblem_on.src="images/emblem_text.gif"
	
}

function chgImg(imgField,newImg){
	if (document.images){
		document[imgField].src=eval(newImg+".src")
	}
	
}