// ----------------------------------------------------------------------
// Javascript form validation routines.
//
// 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 nbsp = 160;    // non-breaking space char
var node_text = 3; // DOM text node-type
var emptyString = /^\s*$/

// -----------------------------------------
//                  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 = required;
};

// -----------------------------------------
//            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", "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;
};




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

function validateUsername(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;

  if (vfld.value.length < 4) {
    msg (ifld, "error", "ERROR: Username is too short (4 chars minimum)");
    vfld.focus();
    return false;
  }

  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", "ERROR: invalid e-mail");
    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", "ERROR: not a valid 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", "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;
};



// -----------------------------------------
// validatePostalCode
// Validate Canadian Postal Code
// Returns true if so (and also if could not be executed because of old browser)
// Permits upper letters and numbers only
// 6 chars with a space in the middle
// -----------------------------------------

function validatePostalCode (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 pfld = trim(vfld.value);  // value of field with whitespace trimmed off
  var postformat = /[ABCEGHJKLMNPRSTVYX][0-9][A-Z] ?[0-9][A-Z][0-9]/i
  if (!postformat.test(pfld)) {
    msg (ifld, "error", "ERROR: Not a valid postal code. Format should be like 'A1B 2C3'");
    vfld.value = vfld.value.toUpperCase();
    vfld.focus();
    return false;
  }
  msg (ifld, "warn", "");
  vfld.value = vfld.value.toUpperCase();
  return true;
};



// -----------------------------------------
//             validateAge
// Validate person's age
// Returns true if OK
// -----------------------------------------

function validateAge    (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);
  var ageRE = /^[0-9]{1,3}$/
  if (!ageRE.test(tfld)) {
    msg (ifld, "error", "ERROR: not a valid age");
    vfld.focus();
    return false;
  }

  if (tfld>=200) {
    msg (ifld, "error", "ERROR: not a valid age");
    vfld.focus();
    return false;
  }

  if (tfld>110) msg (ifld, "warn", "Older than 110: check correct");
  else {
    if (tfld<7) msg (ifld, "warn", "Bit young for this, aren't you?");
    else        msg (ifld, "warn", "");
  }
  return true;
};



// -----------------------------------------
// validatePasswords
// Validate that 2 passwords match
// Returns true if OK
// -----------------------------------------

function validatePasswords  (vfld,   // 1st password to be validated
                             vfld2,  // 2nd password 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 pw1 = trim(vfld.value);
  var pw2 = trim(vfld2.value);

  if (pw1 != pw2) {
      msg (ifld, "error", "Passwords do not match")
      vfld.focus();
      return false;
  }

  if (pw1.length < 5) {
      msg (ifld, "error", "Password must be at least 5 chars.")
      vfld.focus();
      return false;
  }


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

  return true;
};