function preload(imgObj,imgSrc) {
	if (document.images) {
		eval(imgObj+' = new Image()')
		eval(imgObj+'.src = "'+imgSrc+'"')
	}
}

function changeImage(layer,imgName,imgObj) {
	if (document.images) {
		if (document.layers && layer!=null) eval('document.'+layer+'.document.images["'+imgName+'"].src = '+imgObj+'.src')
		else document.images[imgName].src = eval(imgObj+".src")
	}
}

preload('menu_on','gfx/MenuButtonLeftOn.gif')
preload('mainmenu_on','gfx/MenuMainButtonOn.gif')
preload('mainmenu_off','gfx/MenuMainButtonOff.gif')

preload('menu_onG','gfx/MenuButtonLeftOnGreen.gif')
preload('menu_off','gfx/MenuButtonLeftOff.gif')