// ----------------------------------------------------------------------
// 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 displaymsg(fld,     // id of element to display message in
                    msgtype, // class to give element ("validationwarning" or "validationerror")
                    msg)     // 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 displayedmsg;
  if (emptyString.test(msg)) 
    msgfordisplay = String.fromCharCode(nbsp);    
  else  
    msgfordisplay = msg;

  var elem = document.getElementById(fld);
  elem.firstChild.nodeValue = msgfordisplay;  
  
  elem.className = msgtype;   // set the CSS class to adjust appearance of message
}

// --------------------------------------------
//            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) {
      displaymsg (infofield, "validationerror", "ERROR: required");  
      setfocus(valfield);
      return false;
    }
    else {
      displaymsg (infofield, "validationwarning", "");   // OK
      return true;  
    }
  }
  return proceed;
}

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

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

  displaymsg (infofield, "validationwarning", "");  
  return true;
}

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

function validate_email (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 = /^[^@]+@[^@.]+\.[^@]*\w\w$/  ;
  if (!email.test(tfld)) {
    displaymsg (infofield, "validationerror", "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)) 
    displaymsg (infofield, "validationwarning", "Unusual e-mail address - check if correct");
  else
    displaymsg (infofield, "validationwarning", "");
  return true;
}


// --------------------------------------------
//            validate_phone
// 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 validate_phone (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 telnr = /^\+?[0-9 ()-]+[0-9]$/  ;
  if (!telnr.test(tfld)) {
    displaymsg (infofield, "validationerror", "ERROR: not a valid phone number. Use only digits, space, (), - and +");
    setfocus(valfield);
    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<8) {
    displaymsg (infofield, "validationerror", "ERROR: " + numdigits + " digits - too short");
    setfocus(valfield);
    return false;
  }
  
  if (numdigits>14)
    displaymsg (infofield, "validationwarning", numdigits + " digits - check if correct");
  else { 
    if (numdigits<8)
      displaymsg (infofield, "validationwarning", "Only " + numdigits + " digits - check if correct");
    else
      displaymsg (infofield, "validationwarning", "");
  }
  return true;
}


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

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

  if (valfield.value == "---_Please_select_from_list_...") {
    if (required) {
      displaymsg (infofield, "validationerror", "ERROR: make selection");  
      setfocus(valfield);
      return false;
    }
  }
  displaymsg (infofield, "validationwarning", "");   // OK
  return true;  
}


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

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

  displaymsg (infofield, "validationwarning", "");  
  return true;
}