// JScript File
MyImages = new Array();
MyImages[0] = 'images/image_documentation.jpg';
MyImages[1] = 'images/image_homepage.jpg';
MyImages[2] = 'images/image_productinfo.jpg';
MyImages[3] = 'images/image_services.jpg'; 

function newImage() 
{
    document.getElementById("headerimage").setAttribute("src", MyImages[Math.round(Math.random()*3)])
}