code: function() {
  	   Event.addListener(this.el, "change", this.onChange, this, true);
  
         if (YAHOO.env.ua.ie){ // refer to inputEx-95
              var field = this.el;
              new YAHOO.util.KeyListener(this.el, {keys:[13]}, {fn:function(){
                  field.blur();
                  field.focus();
              }}).enable();
         }
  
  	   Event.addFocusListener(this.el, this.onFocus, this, true);
  		Event.addBlurListener(this.el, this.onBlur, this, true);
  	   Event.addListener(this.el, "keypress", this.onKeyPress, this, true);
  	   Event.addListener(this.el, "keyup", this.onKeyUp, this, true);
     }
docs: Register the change, focus and blur events