// JavaScript Document
MyImages=new Array();
    MyImages[0]='images/site/headerimage_01.jpg';
    MyImages[1]='images/site/headerimage_02.jpg';
    MyImages[2]='images/site/headerimage_03.jpg';

    function newImage() 
    {
        document.getElementById("headerimg").setAttribute("src", MyImages[Math.round(Math.random()*2)]);	
    }