var image1 = new Image();
image1.src = "nav_end1.jpg";
var image2 = new Image();
image2.src = "nav_end2.jpg";
var image3 = new Image();
image3.src = "nav_end3.jpg";
var image4 = new Image();
image4.src = "nav_end4.jpg";

function nav_end_ran(){
	var img_name = new Array("nav_end1.jpg", "nav_end2.jpg", "nav_end3.jpg", "nav_end4.jpg");
	var l = img_name.length;
	var rnd_no = Math.floor(l*Math.random());
	document.getElementById("nav_end_img").src = "/images/"+img_name[rnd_no];
}