// 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.

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

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

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

// Delayed focus setting to get around Internet Exploiter bug

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 );
}


// 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 Internet Exploiter 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
};

// Common code for all validation routines to:
// (1) check for older / less-equipped browsers
// (2) 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;
}

var proceed = 2;  

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;
}

// Validate if a radio button or checkbox has been checked
// Returns true if so

function validateChecked   (vfld,   // checkbox to be validated
                            ifld)   // id of element to receive info/error msg
{
  var stat = commonCheck2(vfld, ifld);
  if (stat != proceed) return stat;

  if (vfld.checked) return true;

  // if we get here then the validation has failed

  var errorMsg = 'Please confirm an option';

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

// 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;
};


// Validate if e-mail address is sane
// 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, true);
  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: 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;
};

// ValidateDewars
// Warns if over 10 or equal to zero
// Errors if leading zero on a two-digit number or a non-digit

function validateQuantity (vfld, // element to be validated
			 ifld, // id of element to receive info/error msg
			 reqd) // true if required
{
  var stat = commonCheck (vfld, ifld, true);
  if (stat !=proceed) return stat;
  
  var tfld = trim(vfld.value); // value of field with whitespace trimmed off
  var quantity = /^[0-9]{1,2}$/
  if (!quantity.test(tfld)) {
    msg (ifld, "error", "ERROR: only digits are permitted");
    sefocus(vfld);
    return false;
  }

  var leadingzero = /^0\d$/
    if (leadingzero.test(tfld)) {
      msg (ifld, "error", "ERROR: leading zeroes not permitted");
      setfocus(vfld);
      return false;
    } 

  if (tfld==0)
    msg (ifld, "warn", "Zero given - check if correct");
  else {
    if (tfld>9)
      msg (ifld, "warn", "More than nine given - check if correct");
    else msg (ifld, "warn", "");
  }
  
  return true;
};

// Validate insurance amount

function validateInsurance (vfld, // element to be validated
			    ifld, // id of element to receive info/error msg
			    reqd) // true if required

{
  var stat = commonCheck (vfld, ifld, true);
  if (stat != proceed) return stat;
 
  var tfld = trim(vfld.value);  // value of field with whitespace trimmed off
  var amount = /^\d\d{0,}(.\d{2})?$/
  if (!amount.test(tfld)) {
    msg (ifld, "error", "ERROR: not a valid dollar amount.  Characters permitted are digits and an optional decimal point before two trailing digits.");
    setfocus(vfld);
    return false;
  }

  if (tfld.charAt(0)=='0') {
    msg (ifld, "error", "ERROR: leading zeroes not permitted");
    setfocus(vfld);
    return false;
  }
  
  else msg (ifld, "warn", "");
  return true;
};
  

// 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, true);
  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<6) {
    msg (ifld, "error", "ERROR: " + numdigits + " digits - too short");
    setfocus(vfld);
    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;
};