function validarEmail(valor)
{
  if (/^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/.test(valor))
  {
   return (true);
  }
  else
  {
   return (false);
  }
}



function validar_datos()
{
var txt = "";
	if( document.getElementById('nombre').value == '' )
	{
		txt = txt + "Nombre es Obligatorio \n";
		document.getElementById('nombre').style.background = "#fffed0";
	}
	
	if(  document.getElementById('comentario').value  == '' )
	{
		txt = txt + "Comentario es Obligatorio \n";
		document.getElementById('comentario').style.background = "#fffed0";
	}
	
	if( ! validarEmail(document.getElementById('email').value) )
	{
		txt = txt + "E-mail es Obligatorio \n";
		document.getElementById('email').style.background = "#fffed0";
	}
	
	if( txt != "" ) 
		alert( txt );
	else
	{
		document.getElementById('form_contacto').submit();
	}
	return false;		
}