// ----------------------------------------------------------------------

// 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

}



// --------------------------------------------

//            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", "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;

}



// --------------------------------------------

//               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 = /^[^@]+@[^@.]+\.[^@]*\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;

}





// --------------------------------------------

//            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  (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)) {

    msg (infofield, "error", "ERROR: not a valid telephone number. Characters permitted are digits, space ()- and leading +");

    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<6) {

    msg (infofield, "error", "ERROR: " + numdigits + " digits - too short");

    setfocus(valfield);

    return false;

  }



  if (numdigits>14)

    msg (infofield, "warn", numdigits + " digits - check if correct");

  else { 

    if (numdigits<10)

      msg (infofield, "warn", "Only " + numdigits + " digits - check if correct");

    else

      msg (infofield, "warn", "");

  }

  return true;

}



// --------------------------------------------

//             validateAge

// Validate person's age

// Returns true if OK 

// --------------------------------------------



function validateAge    (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);

  var ageRE = /^[0-9]{1,3}$/

  if (!ageRE.test(tfld)) {

    msg (infofield, "error", "ERROR: not a valid age");

    setfocus(valfield);

    return false;

  }



  if (tfld>=200) {

    msg (infofield, "error", "ERROR: not a valid age");

    setfocus(valfield);

    return false;

  }



  if (tfld>110) msg (infofield, "warn", "Older than 110: check correct");

  else {

    if (tfld<7) msg (infofield, "warn", "Bit young for this, aren't you?");

    else        msg (infofield, "warn", "");

  }

  return true;

}