function toggle(obj) {
	var el = document.getElementById(obj);
	if ( el.style.display != 'none' ) {
		el.style.display = 'none';
	}
	else {
		el.style.display = '';
	}
 }
 
 function cambiaFondo() {
 	var fondo = Math.round(Math.random()*8);
	if (fondo == 0) { fondo = 1;}
 	document.getElementById('home').style.background = '#000 url(img/body-fondo' + fondo + '.jpg) no-repeat fixed 0 0';
 }