autocomplete.js

$(document).ready(function() {
  autocomplete_fields()
});

function autocomplete_fields(){

  $('input.autocomplete').each(function(){

    // lost focus: hide suggestions and select current option
    $(this).focusout(function(){
      hide_and_complete(this);
      return false;
    });

    // mouse up: hide suggestion and select current option
    $(this).mouseup(function(){
        hide_and_complete(this);
        return false;
    });

    // keypress is only used for the return key
    $(this).keypress(function(event){
      if (event.keyCode==13){
        hide_and_complete(this);
        return false;
      }
    });

    $(this).keyup(function(event){
      if(event.keyCode==38){
        var index = find_index('div.autocomplete ul li');
        if (--index < 0){ index = options_count(this)-1}
        $(autocomplete_id(this) + '_' + (index)).addClass('selected').siblings().removeClass('selected')
      }
      if (event.keyCode==40){
        var index = find_index('div.autocomplete ul li');
        if (++index >= options_count(this)){ index = 0; }
        $(autocomplete_id(this) + '_' + (index)).addClass('selected').siblings().removeClass('selected')
      }
      // letters, numbers and backspace trigger the autocomplete search
      if ($(this).val().length >= 2 && ((event.keyCode>45 && event.keyCode<106) || event.keyCode==8)){
        $.get(autocomplete_url(this), null, null, "script");
      }
    return false;
    });

  });
}

function find_index(el){
 var str = $('li.selected');
 return $(el).index(str);
}

function hide_and_complete(el){
  $(el).val($(autocomplete_id(el) + ' .selected').html());
  $(autocomplete_id(el)).hide();
}

function autocomplete_id(el){
  return '#' + $(el).attr('klass') + '_' + $(el).attr('method') + '_autocomplete'
}

function autocomplete_url(el){
  return '/autocomplete/' + $(el).attr('klass') + '/' + $(el).attr('method') + '/' + $(el).val()
}

function options_count(el){
  return $(autocomplete_id(el) + ' ul li').size()
}