//DOM compatible or not?
ie = (document.all) ? true:false; // IE4+
dom = ((document.getElementById) && (!ie)) ? true:false; // Mozilla 

//Help function to add an event listener
function setEventById(id, ev, fu) {
	
	if(dom) {
		document.getElementById(id).addEventListener(ev, fu, false);
	} 
	if(ie) {
		document.getElementById(id).attachEvent('on' + ev, fu);
	}
} 

//Help function to add an event listener
function setEventByObject(ob, ev, fu) {

	if(dom) {
		ob.addEventListener(ev, fu, false);
	} 
	if(ie) {
		ob.attachEvent('on' + ev, fu);
	}	
} 

//Connect eventhandelers to events
setEventById('elephant', 'mouseover', changeImgSourceOver);
setEventById('elephant', 'mouseout', changeImgSourceOut);
setEventByObject(window, 'load', runInterval);

//Changes picture when mouse is over the element
function changeImgSourceOver() {
document.getElementById('elephant').src='/resources/images/Elephnt2.jpg';
}

//Changes picture when the mouse pointer is outside the element
function changeImgSourceOut() {
document.getElementById('elephant').src='/resources/images/Elephnt1.jpg';
}

//Runs every half second
function runInterval() {

	theInterval = window.setInterval("document.getElementById('dancing-elephant').src='/resources/images/Elephnt2.jpg'",500);
	theInterval = window.setInterval("document.getElementById('dancing-elephant').src='/resources/images/Elephnt1.jpg'",500);
}