function menuPreload() {
	var hMenu = document.getElementById('menu');
	if (!hMenu) {
		return;
	}

	var lstImages = hMenu.getElementsByTagName('img');
	if (!lstImages) {
		return;
	}

	for (var iImage = 0; iImage < lstImages.length; iImage++) {
		var lstMatches = /(.+_)lo(\..+)$/.exec(lstImages[iImage].src);

		if (lstMatches) {
			var hImage = new Image();
			hImage.src = lstMatches[1] + 'hi' + lstMatches[2];
		}
	}
}

function menuOver(hTarget) {
	var lstMatches = /(.+_)lo(\..+)$/.exec(hTarget.src);

	hTarget.src = lstMatches[1] + 'hi' + lstMatches[2];
}

function menuOut(hTarget) {
	var lstMatches = /(.+_)hi(\..+)$/.exec(hTarget.src);

	hTarget.src = lstMatches[1] + 'lo' + lstMatches[2];
}

function menuToggle(hTarget, strImg0, strImg1) {
	var strImg0 = strImg0 === undefined ? '' : strImg0;
	var strImg1 = strImg1 === undefined ? '' : strImg1;

	if (strImg1 == '') {
		if (/(.+_)lo(\..+)$/.test(hTarget.src)) {
			menuOver(hTarget);
		} else if (/(.+_)hi(\..+)$/.test(hTarget.src)) {
			menuOut(hTarget);
		}
	} else {
		hTarget.src = RegExp(strImg0 + '$').test(hTarget.src) ? strImg1 : strImg0;
	}
}