// ----------------------------------------------------------------------
// Javascript form validation routines.
// Author: Stephen Poley
//
// Simple routines to quickly pick up obvious typos.
// All validation routines return true if executed by an older browser:
// in this case validation must be left to the server.
//
// Update Aug 2004: have tested that IE 5.0 and IE 5.5 both support DOM model
// sufficiently well, so innerHTML option removed (redundant).
// ----------------------------------------------------------------------

var digits = "0123456789";
var nbsp = 160;    // non-breaking space char
var node_text = 3; // DOM text node-type
emptyString = /^\s*$/;

// non-digit characters which are allowed in ZIP Codes
var ZIPCodeDelimiters = "-";

// our preferred delimiter for reformatting ZIP Codes
var ZIPCodeDelimeter = "-";

// characters which are allowed in Social Security Numbers
var validZIPCodeChars = digits + ZIPCodeDelimiters;

// U.S. ZIP codes have 5 or 9 digits.
// They are formatted as 12345 or 12345-6789.
var digitsInZIPCode1 = 5;
var digitsInZIPCode2 = 9;

// -----------------------------------------
//                  trim
// Trim leading/trailing whitespace off string
// -----------------------------------------

function trim(str)
{
	return str.replace(/^\s+|\s+$/g, '');
};

// -----------------------------------------
//                  msg
// Display warn/error message in HTML element
// commonCheck routine must have previously been called
// -----------------------------------------

function msg(fld,     // id of element to display message in
             msgtype, // class to give element ("warn" or "error")
             message) // string to display
{
	// setting an empty string can give problems if later set to a
	// non-empty string, so ensure a space present. (For Mozilla and Opera one could
	// simply use a space, but IE demands something more, like a non-breaking space.)
	var dispmessage;

	if (emptyString.test(message))
		dispmessage = String.fromCharCode(nbsp);
	else
		dispmessage = message;

	var elem = document.getElementById(fld);

	elem.firstChild.nodeValue = dispmessage;

	elem.className = msgtype;
};

// -----------------------------------------
//            commonCheck
// Common code for all validation routines to:
// (a) check for older / less-equipped browsers
// (b) check if empty fields are required
// Returns true (validation passed),
//         false (validation failed) or
//         proceed (don't know yet)
// -----------------------------------------

var proceed = 2;

function commonCheck    (vfld,   // element to be validated
                         ifld,   // id of element to receive info/error msg
                         reqd)   // true if required
{

	if (!document.getElementById)
		return true;  // not available on this browser - leave validation to the server

	var elem = document.getElementById(ifld);

	if (!elem.firstChild)
		return true;  // not available on this browser

	if (elem.firstChild.nodeType != node_text)
		return true;  // ifld is wrong type of node

	if (emptyString.test(vfld.value))
	{
		if (reqd)
		{
			msg (ifld, "error", "Required");
			vfld.focus();
			return false;
		}
		else
		{
			msg (ifld, "warn", "");   // OK
			return true;
		}
	}

	return proceed;
}

// -----------------------------------------
//            validatePresent
// Validate if something has been entered
// Returns true if so
// -----------------------------------------

function validatePresent(vfld,   // element to be validated
                         ifld )  // id of element to receive info/error msg
{
	var stat = commonCheck (vfld, ifld, true);

	if (stat != proceed)
		return stat;

	msg (ifld, "warn", "");

	return true;
};

// -----------------------------------------
//               validateEmail
// Validate if e-mail address
// Returns true if so (and also if could not be executed because of old browser)
// -----------------------------------------

function validateEmail  (vfld,   // element to be validated
                         ifld,   // id of element to receive info/error msg
                         reqd)   // true if required
{
	var stat = commonCheck (vfld, ifld, reqd);

	if (stat != proceed)
		return stat;

	var tfld = trim(vfld.value);  // value of field with whitespace trimmed off

	var email = /^[^@]+@[^@.]+\.[^@]*\w\w$/;

	if (!email.test(tfld))
	{
		msg (ifld, "error", "Invalid e-mail address");
		vfld.focus();
		return false;
	}

	var email2 = /^[A-Za-z][\w.-]+@\w[\w.-]+\.[\w.-]*[A-Za-z][A-Za-z]$/;

	if (!email2.test(tfld))
		msg (ifld, "warn", "Unusual e-mail address - check if correct");
	else
		msg (ifld, "warn", "");

	return true;
};

// -----------------------------------------
//            validateTelnr
// Validate telephone number
// Returns true if so (and also if could not be executed because of old browser)
// Permits spaces, hyphens, brackets and leading +
// -----------------------------------------

function validateTelnr  (vfld,   // element to be validated
                         ifld,   // id of element to receive info/error msg
                         reqd)   // true if required
{
	var stat = commonCheck (vfld, ifld, reqd);

	if (stat != proceed)
		return stat;

	var tfld = trim(vfld.value);  // value of field with whitespace trimmed off

	var telnr = /^\+?[0-9 ()-]+[0-9]$/
	             if (!telnr.test(tfld))
	             {
		             msg (ifld, "error", "Invalid telephone number. Characters permitted are digits, space ()- and leading +");
		             vfld.focus();
		             return false;
	             }

	             var numdigits = 0;

	for (var j=0; j<tfld.length; j++)
		if (tfld.charAt(j)>='0' && tfld.charAt(j)<='9')
			numdigits++;

	if (numdigits < 6)
	{
		msg (ifld, "error", " " + numdigits + " digits - too short");
		vfld.focus();
		return false;
	}

	if (numdigits > 14)
		msg (ifld, "warn", numdigits + " digits - check if correct");
	else
	{
		if (numdigits < 10)
			msg (ifld, "warn", "Only " + numdigits + " digits - check if correct");
		else
			msg (ifld, "warn", "");
	}

	return true;
};