function muestraGranDiv(){
document.getElementById('granDiv').style.visibility = "visible";
document.getElementById('cargando').style.visibility = "hidden";
}
function changeImages() {
	if (document.images ) {
		for (var i=0; i<changeImages.arguments.length; i+=2) {
			document[changeImages.arguments[i]].src = changeImages.arguments[i+1];
		}
	}
}