// JavaScript Form Validation
var nbsp = 160;    // non-breaking space char
var node_text = 3; // DOM text node-type
var emptyString = /^\s*$/
var glb_vfld;      // retain vfld for timer thread

function trim(str)
{
  return str.replace(/^\s+|\s+$/g, '') //match any number Unicode whitespace, at end or beginning
}

function setFocusDelayed()
{
  glb_vfld.focus()
}

function setfocus(vfld)
{
  // save vfld in global variable so value retained when routine exits
  glb_vfld = vfld;
  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    (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");  
      setfocus(vfld);
      return false;
    }
    else {
      msg (ifld, "warn", "");   // OK
      return true;  
    }
  }
  return proceed;
}

// -----------------------------------------
//            commonCheck2
// Common code for checkbox validation routines to
// check for older / less-equipped browsers
// Returns true (validation passed) or
//         proceed (don't know yet)
// -----------------------------------------

function commonCheck2   (vfld,   // element to be validated
                         ifld)   // id of element to receive info/error msg
{
  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  

  msg (ifld, "warn", "");  // clear any previous error message
  return proceed;
}

// -----------------------------------------
//            validateNumr
// Validate numeric-only field
// Returns true if so (and also if could not be executed because of old browser)
// -----------------------------------------

function validateNumr  (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 numr = /^[0-9]*$/
  if (!numr.test(tfld)) {
    msg (ifld, "error", "ERROR: Must be numbers only");
    setfocus(vfld);
    return false;
  }
  return true;
}

// -----------------------------------------
//            validateNumrNDig
// Validate numeric-only field, number of digits at least "n"
// Returns true if so (and also if could not be executed because of old browser)
// -----------------------------------------

function validateNumrNDig (vfld,     // element to be validated
                           ifld,     // id of element to receive info/error msg
                           reqd,     // true if required
						   NDigits)  // number of digits required
{
  if (validateNumr(vfld, ifld, reqd)) {

	var tfld = trim(vfld.value);  // value of field with whitespace trimmed off
    var numdigits = tfld.length;
	
	if (numdigits<NDigits) {
	  msg (ifld, "error", "ERROR: " + numdigits + " digits - too short");
	  setfocus(vfld);
	  return false;
	}
	else 
	  return true;
  }
  else 
    return false;
}

// -----------------------------------------
//            validateCheckbox
// Validate that the correct number of checkboxes has been checked.
// Returns true if valid (and also if could not be executed because 
// of old browser)
// -----------------------------------------
function validateCheckbox  (vfld,   // checkboxes to be validated
                            ifld,   //, id of element to receive info/error msg
                            nr,     // number of checkboxes to be checked. [>=2 in original code]
                            cond)   // condition: -1 = less than or equal to nr
                                    //             0 = equal to nr (default)
                                    //             1 = greater than or equal to nr
{
//  if (!nr || nr<2) {
//    alert('Programming error in validateCheckbox: nr<2'); 
//        for nr=1 use radio buttons or validateConfirm
//    return true;
//  }
  if (!cond) cond = 0;

  var stat = commonCheck2(vfld, ifld);
  if (stat != proceed) return stat;

  // count how many boxes have been checked by the reader
  var count = 0;
  for (var j=0; j<vfld.length; j++)
     if (vfld[j].checked) count++;

  if (count==nr) return true;
  if (count<nr && cond==-1) return true;
  if (count>nr && cond==1)  return true;

  // if we get here then the validation has failed

  var suffix='';
  if (count>1) suffix='es';

  var errorMsg;

  if (count<nr) errorMsg = 'Only ' + count + ' box' + suffix + ' checked: ' + nr + ' required';
  if (count>nr) errorMsg = '' + count + ' boxes checked: maximum ' + nr + ' allowed';
  if (count==0) errorMsg = 'No boxes checked: ' + nr + ' required';

  msg (ifld, "error", errorMsg);
  return false;
}

// -----------------------------------------
//            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;
}

// -----------------------------------------
//            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 +");
    setfocus(vfld);
    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<7) {
    msg (ifld, "error", "ERROR: " + numdigits + " digits - too short");
    setfocus(vfld);
    return false;
  }
  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$/	//not-@, @, not-@, ., not-@ letter-letter
  if (!email.test(tfld)) {
    msg (ifld, "error", "ERROR: not a valid e-mail address");
    setfocus(vfld);
    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;
}