function fadeOut() {
	var myFx = new Fx.Tween('contenedor');
	myFx.start('opacity', 0);
	
	myFx.onComplete = function(){
		ruta = "nutricion_salud/busqueda.php";
		postDataReturnText(ruta, showResults, 'frm_buscar');
	}
}

function fadeIn() {
	var myFx = new Fx.Tween('contenedor');
	myFx.start('opacity', 1);
}

function showResults(text) {
	document.getElementById('contenedor').innerHTML = text;
	
	fadeIn();
}