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

// preload rollover graphics
preload('urelOn','urelb.gif')
preload('urelOff','urela.gif')
preload('ucbOn','ucbb.gif')
preload('ucbOff','ucba.gif')
preload('vcOn','vcb.gif')
preload('vcOff','vca.gif')
preload('foundationOn','foundb.gif')
preload('foundationOff','founda.gif')
preload('unitsOn','unitsb.gif')
preload('unitsOff','unitsa.gif')
preload('sitesOn','sitesb.gif')
preload('sitesOff','sitesa.gif')
preload('indexOn','indexb.gif')
preload('indexOff','indexa.gif')
preload('navinfo','wht_dot.gif')
preload('infourel','infourel.gif')
preload('infoucb','infoucb.gif')
preload('infovc','infovc.gif')
preload('infofound','infofound.gif')
preload('infounits','infounits.gif')
preload('infosites','infosites.gif')
preload('infoindex','infoindex.gif')

function on(imageName) {
	if (document.images) {
		document[imageName].src = eval(imageName + "On.src");
	}
}

function off(imageName) {
  if (document.images) {
    document[imageName].src = eval(imageName + "Off.src");
  }
}

function changeImages() {
  if (document.images) {
    for (var i=0; i<changeImages.arguments.length; i+=2) {
      document[changeImages.arguments[i]].src = eval(changeImages.arguments[i+1] + ".src");
    }
  }
}