function conpru(){
if(document.form3.palabra.value==""){
alert("Por favor, ponga un concepto a buscar.");
return false;
}
}
function cerrar(){
document.getElementById('anuncio').style.visibility = 'hidden' ;
}
function cerrarmail(){
document.getElementById('condi').style.visibility = 'hidden' ;
}
function vermail(){
document.getElementById('condi').style.visibility = 'visible' ;
}

function conpru(){
if(document.form3.palabra.value==""){
alert("Por favor, ponga un concepto a buscar.");
return false;
}
}
 function cambiarHojaEstilos (id) {
 	if(id=="book"){
	document.getElementById('book').style.display='block';
	document.getElementById('noticia3').style.display='none';
	}else if(id=="noticia"){
	document.getElementById('book').style.display='none';
	document.getElementById('noticia3').style.display='block';
	

	}
 }