// Based on Nicholas C. Zakas' "Make Life Easy With Autocomplete Textboxes"
// http://www.sitepoint.com/article/life-autocomplete-textboxes
//
// Only modification is making the comparison case-insensitive.

var isOpera = navigator.userAgent.indexOf('Opera') > -1;
var isIE = navigator.userAgent.indexOf('MSIE') > 1 && !isOpera;
var isMoz = navigator.userAgent.indexOf('Mozilla/5.') == 0 && !isOpera;

function textboxSelect (oTextbox, iStart, iEnd) {
 switch(arguments.length) {
  case 1:
   oTextbox.select();
   break;
  case 2:
   iEnd = oTextbox.value.length;
   /* falls through */
  case 3:          
   if (isIE) {
    var oRange = oTextbox.createTextRange();
    oRange.moveStart("character", iStart);
    oRange.moveEnd("character", -oTextbox.value.length + iEnd);      
    oRange.select();                                              
   }
   else if (isMoz){
    oTextbox.setSelectionRange(iStart, iEnd);
   }                    
 }
 oTextbox.focus();
}

function textboxReplaceSelect (oTextbox, sText) {
 if (isIE) {
  var oRange = document.selection.createRange();
  oRange.text = sText;
  oRange.collapse(true);
  oRange.select();                                
 }
 else if (isMoz) {
  var iStart = oTextbox.selectionStart;
  oTextbox.value = oTextbox.value.substring(0, iStart) + sText + oTextbox.value.substring(oTextbox.selectionEnd, oTextbox.value.length);
  oTextbox.setSelectionRange(iStart + sText.length, iStart + sText.length);
 }
 oTextbox.focus();
}

function autocompleteMatch (sText, arrValues) {
 for (var i=0; i < arrValues.length; i++) {
  if (arrValues[i].toLowerCase().indexOf(sText) == 0) {
   return arrValues[i];
  }
 }
 return null;
}

function autocomplete(oTextbox, oEvent, arrValues) {
 switch (oEvent.keyCode) {
  case 38: //up arrow  
  case 40: //down arrow
  case 37: //left arrow
  case 39: //right arrow
  case 33: //page up  
  case 34: //page down  
  case 36: //home  
  case 35: //end                  
  case 13: //enter  
  case  9: //tab  
  case 27: //esc  
  case 16: //shift  
  case 17: //ctrl  
  case 18: //alt  
  case 20: //caps lock
  case  8: //backspace  
  case 46: //delete
  return true;
  break;
 default:
  textboxReplaceSelect(oTextbox, String.fromCharCode(isIE ? oEvent.keyCode : oEvent.charCode));
  var iLen = oTextbox.value.length;
  var sMatch = autocompleteMatch(oTextbox.value.toLowerCase(), arrValues);
  if (sMatch != null) {
   oTextbox.value = sMatch;
   textboxSelect(oTextbox, iLen, oTextbox.value.length);
  }  
  return false;
 }
}