Object.extend(Autocompleter.Base.prototype,{
  baseInitialize: function(element, update, options) {
    element          = $(element)
    this.element     = element; 
    this.update      = $(update);  
    this.hasFocus    = false; 
    this.changed     = false; 
    this.active      = false; 
    this.index       = 0;     
    this.entryCount  = 0;
    this.oldElementValue = this.element.value;

    if(this.setOptions)
      this.setOptions(options);
    else
      this.options = options || { };

    this.options.paramName    = this.options.paramName || this.element.name;
    this.options.tokens       = this.options.tokens || [];
    this.options.frequency    = this.options.frequency || 0.4;
    this.options.minChars     = this.options.minChars || 1;
    this.options.onShow       = this.options.onShow || 
    function(element, update){ 
      if(!update.style.position || update.style.position=='absolute') {
        update.style.position = 'absolute';
        /*
        Position.clone(element, update, {
          setHeight: false,
          setWidth: false,
          offsetTop: element.offsetHeight
        });
        */
      }
      Effect.Appear(update,{duration:0.15});
    };

    this.options.onHide = this.options.onHide || 
      function(element, update){ new Effect.Fade(update,{duration:0.15}) };

    if(typeof(this.options.tokens) == 'string') 
      this.options.tokens = new Array(this.options.tokens);
    // Force carriage returns as token delimiters anyway
    if (!this.options.tokens.include('\n'))
      this.options.tokens.push('\n');

    this.observer = null;

    this.element.setAttribute('autocomplete','off');

    Element.hide(this.update);

    Event.observe(this.element, 'blur', this.onBlur.bindAsEventListener(this));
    Event.observe(this.element, 'keydown', this.onKeyPress.bindAsEventListener(this));
  },


  markPrevious: function() {
    if(this.index>0)
      this.index--;
    else
      this.index=this.entryCount-1;
  },
  
  markNext: function() {
    if(this.index<this.entryCount-1)
      this.index++
    else
      this.index=0;
  }
});