Events not fired when Iframe present on page

Events not fired when Iframe present on page

Hi, I am having problems with with event firing when an Iframe is present on the page. Once I remove the IFrame, everything works fine. Please note that the control has the focus when I press Enter key ( I read some articles that this might be the problem). I tried both in IE8 and Firefox. Here is my code:
 
<
html xmlns ="http://www.w3.org/1999/xhtml">
      < head runat ="server">
            < title ></ title >
            < script type ="text/javascript" src ="/script/jquery-1.4.3.min.js"></ script >
      </ head >
      < body >
            < form id ="form1" runat ="server" >
            < input style = " width : 100px" id ="target" type ="text" />
            < iframe id ="frameid" style =" width :1px; height :1px; z-index :-1; position :absolute; left :-500px; top :-500px"/>
            < script type ="text/javascript">
                  $( document ).ready( function () {
                        $( '#target' ).keydown( function (event) {
                        alert(event.which);
                        });
                  });
            </ script >
            </ form >
      </ body >
</ html >