/* create a random number to chose image */
var rand1 = Math.floor(Math.random()*4)+1;

/* create an array of images to utilise the rand outcome */
imageChoice = new Array(4);

imageChoice[1] = "rotate-1.jpg";
imageChoice[2] = "rotate-2.jpg";
imageChoice[3] = "rotate-3.jpg";
imageChoice[4] = "rotate-4.jpg";


/* write the images to the page */
function writeImage() {
	var oObj = document.getElementById("banner-img");
	
	oObj.style.backgroundImage = "url('http://www.canberra.edu.au/faculties/education/nested-content/random-images/" + imageChoice[rand1] +"')";
	oObj.style.backgroundRepeat = "no-repeat";
	oObj.style.backgroundPosition = "top right";
}