//init bouton

var pageLoad = function()
{
    var elements = YAHOO.util.Dom.getElementsByClassName('BtnHover', 'img'); 

    for(i=0; i<elements.length;i++)
    {
        YAHOO.util.Event.addListener(elements[i], 'mouseover',  function(){this.src = this.src.replace('.gif','Hover.gif');} );
        YAHOO.util.Event.addListener(elements[i], 'mouseout', function(){this.src = this.src.replace('Hover.gif','.gif');} );
	}
};

YAHOO.util.Event.addListener(window, 'load', pageLoad);