window.onload = initAll;

function initAll() {
	var i=0;
	for(i=0;i<=document.images.length;i++) {
		var currImg = document.images[i];
		setupSwitch(currImg);
	}
}

function setupSwitch(theImg) {
		if(theImg.className=="navtab") {
				var overImg = new Image();
				overImg.src = "http://www.frogdogquotes.com/wp-content/themes/frogdog/images/" + theImg.name + "_on.png";
				theImg.onmouseover=function() {
					theImg.src = overImg.src;
				}
				theImg.onmouseout=function() {
					theImg.src = "http://www.frogdogquotes.com/wp-content/themes/frogdog/images/" + theImg.name + ".png";
				}
		}
}