var whitespace = " \t\n\r";
var iEmail = "La direcion de correo insertada no es correcta (ejemplo foo@bar.com). porfavor vuelva a intrucirla de nuevo."
function warnInvalid (theField, s)
{   theField.focus()
    theField.select()
    alert(s)
    return false
}
function isWhitespace (s)

{   var i;

    // Is s empty?
    if (isEmpty(s)) return true;

    // Search through string's characters one by one
    // until we find a non-whitespace character.
    // When we do, return false; if we don't, return true.

    for (i = 0; i < s.length; i++)
    {   
        // Check that current character isn't whitespace.
        var c = s.charAt(i);

        if (whitespace.indexOf(c) == -1) return false;
    }

    // All characters are whitespace.
    return true;
}	
function isEmpty(s)
{   return ((s == null) || (s.length == 0))
}
function isEmail (s)
{   if (isEmpty(s)) 
       if (isEmail.arguments.length == 1) return defaultEmptyOK;
       else return (isEmail.arguments[1] == true);
   
    // is s whitespace?
    if (isWhitespace(s)) return false;
    
    // there must be >= 1 character before @, so we
    // start looking at character position 1 
    // (i.e. second character)
    var i = 1;
    var sLength = s.length;

    // look for @
    while ((i < sLength) && (s.charAt(i) != "@"))
    { i++
    }

    if ((i >= sLength) || (s.charAt(i) != "@")) return false;
    else i += 2;

    // look for .
    while ((i < sLength) && (s.charAt(i) != "."))
    { i++
    }

    // there must be at least one character after the .
    if ((i >= sLength - 1) || (s.charAt(i) != ".")) return false;
    else return true;
}

function muestra_capa(nombre_capa,f) {
	
   if(nombre_capa.style.display=="none"){	
      nombre_capa.style.display = "block";
	  f.email.focus();
          
   }
   else{
	    nombre_capa.style.display = "none";
   }	   
}

function validate_form(f){
		if(f.email.value=="") {
			alert("El campo E-mail tiene que estar relleno");
			f.email.focus();
			return false;
		}
		if(f.mensaje.value=="") {
			alert("El Mensaje tiene que esta relleno");
			f.mensaje.focus();
			return false;
		}
		if (!checkEmail(f.email,false)) {
			return false;
		}
	f.submit()
	}

function checkEmail (theField, emptyOK)
{   if (checkEmail.arguments.length == 1) emptyOK = defaultEmptyOK;
    if ((emptyOK == true) && (isEmpty(theField.value))) return true;
    else if (!isEmail(theField.value, false)) 
       return warnInvalid (theField, iEmail);
    else return true;
}