function imgOn(imgName, imgsrc) {
if (document.images) {
teston = new Image(); 
document[imgName].src =  imgsrc;
}
}

function imgOff(imgName, imgsrc) {
if (document.images) {
testoff = new Image(); 
testoff.src = imgsrc;
document[imgName].src =  testoff.src;
}
}

function preloadImages() {
	if (document.images) {
		preload0 = new Image(160, 45);
		preload0.src ="images/colbox_0_2.gif";
		preload1 = new Image(160, 45);
		preload1.src ="images/colbox_1_2.gif";
		preload2 = new Image(160, 45);
		preload2.src ="images/colbox_2_2.gif";
		preload3 = new Image(160, 45);
		preload3.src ="images/colbox_3_2.gif";
		preload4 = new Image(160, 45);
		preload4.src ="images/colbox_4_2.gif";
	}
}