function howlong (s) {
        return s.length;
}
                                                                                                                                             
var main_form;                                                                                                                                             
function get_pin(form) {
        main_form = form;
        if( isWhitespace(form.code1.value) || isWhitespace(form.code2.value) ) return;

        var code3 = form.code3.value;
        var idx = howlong(code3);
        if (  idx > 0 && howlong(form.pin.value) == 0 &&
                (code3.charAt(idx-1) == 'x' || code3.charAt(idx-1) == 'X' ) ) {
               var acode = form.code1.value + form.code2.value + code3;
                                                                      
               show_divwin(getpin_str, 400, 240);
               setTimeout( "document.pinform.pin1.focus();", 200);
               if(need_selectbook(acode)) load_books(acode);
        }
        if (  idx > 0 && (code3.charAt(idx-1) == 'z' || code3.charAt(idx-1) == 'Z' ||
           code3.charAt(idx-1) == 'y' || code3.charAt(idx-1) == 'Y' ) ) {
               var acode = form.code1.value + form.code2.value + code3;
               window.location.href="/nt/register.cgi?acode=" + acode; 
        }        
}
                                                                                                                                             
function set_pin(form) {
  if (all_entered(form)){
    main_form.pin.value = form.pin1.value + form.pin2.value + form.pin3.value + form.pin4.value + form.pin5.value;
    check_acode(main_form);
  }
}

function show_divwin(str, w, h){
  getDiv("pop_win").style.visibility = "visible";
  getDiv("pop_win").innerHTML = '<table align="center" valign="middle" style="background:#FFFFFF;border: 2px ridge #DDDDDD;'+
        'width:' + w + '; height:' + h + ';">'+
        '<tr><td align="center">' + str +
        '</td></tr></table>';
}
                                                                                                                                             
function hide_divwin(){
  getDiv("pop_win").innerHTML = '';
  getDiv("pop_win").style.visibility = "hidden";
}

var browserName = navigator.appName;  //BROWSER NAME
var browserVer = parseFloat(navigator.appVersion);  //BROWSERVERSION
                                                                                                                                             
var netscape = "";
                                                                                                                                             
if (browserName == "Netscape") {
  netscape = true;
}
                                                                                                                                             
function autoTab(input, len, nextf, e) {
  var keyCode = (netscape) ? e.which : e.keyCode;
  var filter = (netscape) ? [0,8,9] : [0,8,9,16,17,18,37,38,39,40,46];
  if(input.value.length >= len && !containsElement(filter,keyCode)) {
    input.value = input.value.slice(0, len);
    nextf.focus();
  }
  return true;
}
                                                                                                                                             
function containsElement(ft, kc) {
 var found = false, index = 0;
 while(!found && index < ft.length){
  if(ft[index] == kc)
   found = true;
  else
   index++;
 }
 return found;
}

function getDiv(id, doc){
        var mydiv;
        if( doc == null) doc= this.document;
                                                                                                                                             
        if(document.all && !document.getElementById){
          mydiv = doc.all[id];
        }else if(document.getElementById){
          mydiv = doc.getElementById(id);
        }
        return mydiv;
}
                                                                                                                                             
function isWhitespace (s) {
        var i;
                                                                                                                                             
        if ((s == null) || (s.length == 0)) return true;
                                                                                                                                             
        return ((typeof s=="string")&&(s.search(/^\s*$/)==0));
}
                                                                                                                                             
function check_acode(form){
   var acode = form.code1.value + form.code2.value + form.code3.value;
                                                                                                                                             
   if(need_selectbook(acode)) {
     select_book();
     return;
   }
   hide_divwin("pop_win");
}
                                                                                                                                             
function need_selectbook(acode){
   for(i=0; i<acode_x.length; i++){
      if(acode_x[i] == acode) {
        return true;
      }
   }
   return false;
}
                                                                                                                                             
var book_id = new Array();
var book_name = new Array();

function load_books(acode){
 var now = new Date();
 book_loader.location.href ="select_book.cgi?acode=" + acode + "&ts=" + now.getTime();
}
                                                                                                                                             
function extract_bookdata(doc){
        var bookNames = doc.getElementById("bookname").childNodes;
        var bookIDs = doc.getElementById("bookid").childNodes;
        var totalBook = bookNames.length;
        for (var i=0; i<totalBook; i++) {
             if (bookNames[i].nodeType == 1 && bookIDs[i].nodeType == 1){
                  var indx = book_id.length;
                  book_id[indx] =   bookIDs[i].id;
                  book_name[indx] = bookNames[i].id;
             }
        }
}
function select_book(){
     show_divwin(selectbook_str, 580, 240);
     setTimeout("fill_bookmenu()",200);
}

function fill_bookmenu(){
     var book_list = document.selectbookform.textbook;
     if( book_list.length > 1 ){
          book_list.length = 0;
          book_list.options[0] =  new Option( "Select Textbook", -1, false, false);
     }
     for( var i=0; i<book_id.length; i++){
        var oindx = book_list.length;
        book_list.options[oindx] = new Option( book_name[i], book_id[i], false, false);
     }
     document.selectbookform.textbook.focus();
}
                                                                                                                                             
function all_entered(form){
  if ( isWhitespace(form.pin1.value +
                    form.pin2.value +
                    form.pin3.value +
                    form.pin4.value +
                    form.pin5.value) ){
       alert("Please enter pin number");
       form.pin1.focus();
       return false;
  }
  if ( isWhitespace(form.pin1.value) ||
       isWhitespace(form.pin2.value) ||
       isWhitespace(form.pin3.value) ||
       isWhitespace(form.pin4.value) ||
       isWhitespace(form.pin5.value) ){
       alert("Please enter correct pin number");
       form.pin1.focus();
       return false;
  }
  return true;
}
function check_selection(field){
                                                                                                                                             
   if ( not_selected(field) ){
         alert('Please select a textbook.');
         return false;
    }
    bookid = field.options[field.selectedIndex].value;
    main_form.bid.value=bookid;
    hide_divwin("pop_win");
}
                                                                                                                                             
function not_selected(field) {
   var i;
   if ( field != null && field.selected){
     return false;
   } else {
     for (i=1; i<field.length; i++) {
        if ( field[i].selected ) {
            return false;
        }
     }
  }
  return true;
}