// ----------------------------------------------------------------------
// 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 Jun 2005: discovered that reason IE wasn't setting focus was
// due to an IE timing bug. Added 0.1 sec delay to fix.
//
// Update Oct 2005: minor tidy-up: unused parameter removed
//
// Update Jun 2006: minor improvements to variable names and layout
// ----------------------------------------------------------------------

var nbsp = 160;		// non-breaking space char
var node_text = 3;	// DOM text node-type
var emptyString = /^\s*$/ ;
var global_valfield;	// retain valfield for timer thread

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

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


// --------------------------------------------
//                  setfocus
// Delayed focus setting to get around IE bug
// --------------------------------------------

function setFocusDelayed()
{
  global_valfield.focus();
}

function setfocus(valfield)
{
  // save valfield in global variable so value retained when routine exits
  global_valfield = valfield;
  setTimeout( 'setFocusDelayed()', 100 );
}


// --------------------------------------------
//                  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;   // set the CSS class to adjust appearance of message
  
}

// --------------------------------------------
//            checkDigit
// Check to see if char is a digit
// Returns true if so 
// --------------------------------------------
function checkDigit(valfield,   // element to be validated 
                    e,          // event
                    infofield ) // id of element to receive info/error msg
{  
  e = (e) ? e : window.event
  var charCode = (e.which) ? e.which : e.keyCode
  if (charCode > 31 && (charCode < 48 || charCode > 57)) {
    msg (infofield, "error", "ERROR: must be a digit");
    setfocus(valfield);
    return false;
  }
  msg (infofield, "warn", "");  
  return true;
}

// --------------------------------------------
//            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    (valfield,   // element to be validated
                         infofield,  // id of element to receive info/error msg
                         required)   // true if required
{
  if (!document.getElementById) 
    return true;  // not available on this browser - leave validation to the server
  var elem = document.getElementById(infofield);
  if (!elem.firstChild) return true;  // not available on this browser 
  if (elem.firstChild.nodeType != node_text) return true;  // infofield is wrong type of node  

  if (emptyString.test(valfield.value)) {
    if (required) {
      msg (infofield, "error", "ERROR: required");  
      setfocus(valfield);
      return false;
    }
    else {
      msg (infofield, "warn", "");   // OK
      return true;  
    }
  }
  return proceed;
}

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

function validatePresent(valfield,   // element to be validated
                         infofield ) // id of element to receive info/error msg
{
  var stat = commonCheck (valfield, infofield, true);
  if (stat != proceed) return stat;

  msg (infofield, "warn", "");  
  return true;
}

// --------------------------------------------
//            validateAgreement
// Validate if the agreement check box is checked
// Returns true if so 
// --------------------------------------------

function validateAgreement(valfield,   // element to be validated
                           infofield ) // id of element to receive info/error msg
{
  var stat = commonCheck (valfield, infofield, true);
  if (stat != proceed) return stat;

  if (!valfield.checked)
  {
    msg (infofield, "error", "ERROR: agreement box must be checked");
    setfocus(valfield);
    return false;
  }
  msg (infofield, "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  (valfield,   // element to be validated
                         infofield,  // id of element to receive info/error msg
                         required)   // true if required
{
  var stat = commonCheck (valfield, infofield, required);
  if (stat != proceed) return stat;

  var tfld = trim(valfield.value);  // value of field with whitespace trimmed off
  var email = /^[a-zA-Z][\w\.-]*[a-zA-Z0-9]@[a-zA-Z0-9][\w\.-]*[a-zA-Z0-9]\.[a-zA-Z][a-zA-Z\.]*[a-zA-Z]$/ ;
  if (!email.test(tfld)) {
    msg (infofield, "error", "ERROR: not a valid e-mail address");
    setfocus(valfield);
    return false;
  }
  msg (infofield, "warn", "");
  return true;

//  var email = /^[^@]+@[^@.]+\.[^@]*\w\w$/  ;
//  if (!email.test(tfld)) {
//    msg (infofield, "error", "ERROR: not a valid e-mail address");
//    setfocus(valfield);
//    return false;
//  }

//  var email2 = /^[A-Za-z][\w.-]+@\w[\w.-]+\.[\w.-]*[A-Za-z][A-Za-z]$/  ;
//  if (!email2.test(tfld)) 
//    msg (infofield, "warn", "Unusual e-mail address - check if correct");
//  else
//    msg (infofield, "warn", "");
//  return true;
}


// --------------------------------------------
//            validatePhone
// Validate telephone number field - called separately for area code, 3-digit prefix and 4-digit number
// Returns true if so (and also if could not be executed because of old browser)
// --------------------------------------------

function validatePhone (valfield,   // element to be validated
                         infofield,  // id of element to receive info/error msg
						 numdigits,  // number of digits in field
                         required)   // true if required
{
  var stat = commonCheck (valfield, infofield, required);
  if (stat != proceed) return stat;

  var tfld = trim(valfield.value);  // value of field with whitespace trimmed off
  var digitcount = 0;
  for (var j=0; j<tfld.length; j++)
    if (tfld.charAt(j)>='0' && tfld.charAt(j)<='9') digitcount++;

  if (digitcount<numdigits) {
    msg (infofield, "error", "ERROR: xxx xxx xxxx format required");
    setfocus(valfield);
    return false;
  }

  return true;
}