var imglist = new Array(
	"./images/top-img01.jpg",
	"./images/top-img02.jpg",
	"./images/top-img03.jpg",
	"./images/top-img04.jpg"
	);
var selectnum = Math.floor((Math.random() * 100)) % imglist.length;
var output = "<img src=" + imglist[selectnum] + ">";
document.write(output);