// ----------------------------------------------------------------------
// Javascript form validation routines.
// Author: Stephen Poley
//
// File 2: checkboxes
// Uses the msg routine from formval.js
// ----------------------------------------------------------------------


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

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;
}



// -----------------------------------------
//            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. >=1
                            cond)   // condition: -1 = less than or equal to nr
                                    //             0 = equal to nr (default)
                                    //             1 = greater than or equal to nr
{
  if (!nr || nr<1) {
    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;
}


// -----------------------------------------
//            validateConfirm 
// Usually one doesn't want to validate if 1 checkbox of a set has been
// checked, because in this case one would use radio buttons instead.
// But sometimes one wants a reader to check a single box to confirm that 
// he or she agrees to something. That is covered by this routine.
//
// Returns true if valid (and also if could not be executed because 
// of old browser)
// -----------------------------------------

function validateConfirm   (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 read the above message and confirm you agree to it';

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