function preloadImages() {
	
	imgDir = 'images/';
	imgExt = '.png';
	
	if (document.images) {
		//preload main images
		
		img01 = new Image();
		img01.src = imgDir + 'cpi_01' + imgExt
		img02 = new Image();
		img02.src = imgDir + 'cpi_02' + imgExt
		img03 = new Image();
		img03.src = imgDir + 'cpi_03' + imgExt
		img04 = new Image();
		img04.src = imgDir + 'cpi_04' + imgExt
		img05 = new Image();
		img05.src = imgDir + 'cpi_05' + imgExt
		img06 = new Image();
		img06.src = imgDir + 'cpi_06' + imgExt
		img07 = new Image();
		img07.src = imgDir + 'cpibanner' + imgExt
		img08 = new Image();
		img08.src = imgDir + 'cpibannerback' + imgExt
		
		//preload menu images
		home = new Image();
		home.src = imgDir + 'cpihome' + imgExt;
		homeon = new Image();
		homeon.src = imgDir + 'cpihomeover' + imgExt;
		
		about = new Image();
		about.src = imgDir + 'cpiabout' + imgExt;
		abouton = new Image();
		abouton.src = imgDir + 'cpiaboutover' + imgExt;
		
		services = new Image();
		services.src = imgDir + 'cpiservices' + imgExt;
		serviceson = new Image();
		serviceson.src = imgDir + 'cpiservicesover' + imgExt;
		
		products = new Image();
		products.src = imgDir + 'cpiproducts' + imgExt;
		productson = new Image();
		productson.src = imgDir + 'cpiproductsover' + imgExt;
		
		blog = new Image();
		blog.src = imgDir + 'cpiblog' + imgExt;
		blogon = new Image();
		blogon.src = imgDir + 'cpiblogover' + imgExt;
		
		resources = new Image();
		resources.src = imgDir + 'cpiresources' + imgExt;
		resourceson = new Image();
		resourceson.src = imgDir + 'cpiresourcesover' + imgExt;
		
		contact = new Image();
		contact.src = imgDir + 'cpicontact' + imgExt;
		contacton = new Image();
		contacton.src = imgDir + 'cpicontactover' + imgExt;
		}
}

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

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

preloadImages();