function validar()
  {
   if(document.getElementById('cadena').value=="")
     {
	   alert ("Ingresa un nombre para generar la búsqueda");
	   return false;
	 }
   else
     return true; 
  }
  
 function abrir_contacto()
  {
	window.open("contacto.html","Contacto","width=450,height=600,scrollbars=yes");  
  }
  
  function abrir_legal()
  {
	window.open("legal.html","Contacto","width=450,height=600,scrollbars=yes");  
  }
  function abrir_submit()
  {
	window.open("submit.html","Contacto","width=450,height=600,scrollbars=yes");  
  }