// JavaScript Document

window.onload = function(){
var url=[];
url[0] = 'objectnav-bg01.jpg';
url[1] = 'objectnav-bg02.jpg';
url[2] = 'objectnav-bg03.jpg';
url[3] = 'objectnav-bg04.jpg';
var n = Math.floor(Math.random() * url.length);
var elm = document.getElementById('objectnav');
elm.style.backgroundImage = 'url(images/' + url[n] + ')';
};