img = new Array();
img[0] = "./images/top_img01.jpg";
img[1] = "./images/top_img02.jpg";
img[2] = "./images/top_img03.jpg";

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