img = new Array();
img[0] = "images/top_sans_black.jpg";
img[1] = "images/top_sans_color.jpg";
img[2] = "images/top_serif_black.jpg";
img[3] = "images/top_serif_color.jpg";

function setBanner(){
	amount = img.length;
	No = Math.floor(Math.random()*amount);
	document.write("<img src='" + img[No] + "' border='0'>");
}