function menuInit(ul) {
	var ul = xFirstChild(document.getElementById('menu'), 'UL');
	var li = xFirstChild(ul, 'LI');
	var img;

	do {	
        img = xFirstChild(xFirstChild(li, 'A'), 'IMG');
        
        if (img.src.match(/_actif\.gif$/)) {
            continue;
        }
        
		YAHOO.util.Event.addListener(img, "mouseover", menuImgOnMouseOver, img);
		YAHOO.util.Event.addListener(img, "mouseout" , menuImgOnMouseOut, img);
	} while (li = xNextSib(li, 'LI'));
}

function menuImgOnMouseOver() {
    this.src = this.src.replace(/\.gif$/, '_actif.gif');
}

function menuImgOnMouseOut() {
    this.src = this.src.replace(/_actif\.gif$/, '.gif');
}