function initRollovers() {
	if(document.getElementsByTagName) {
		// get all images on the page
		var allImages = document.getElementsByTagName("img");
		var rolloverOn = [];
		for(var i = 0; i < allImages.length; i++) {
			// check that the image is a rollover
			if(allImages[i].src.indexOf("_off.") != -1) {
				// preload the rollover
				var rolloverImage = new Image();
				var imageSrc = allImages[i].src.replace(/_off./,"_on.");
				rolloverImage.src = imageSrc;
				// put the rollover into the rollover array
				rolloverOn.push(rolloverImage);
				// add mouseover and mouseout events
				allImages[i].onmouseover = function(){this.src = this.src.replace(/_off./,"_on.");};
				allImages[i].onmouseout = function(){this.src = this.src.replace(/_on./,"_off.");};
			}
		}
	}
}
if (window.addEventListener) {
	window.addEventListener("load", initRollovers, false);
} else if (window.attachEvent) {
	window.attachEvent("onload", initRollovers);
}