getElementById in jQuery

How can I safely convert this to jQuery, specially the prompt part without any problems with IE.

<script type="text/javascript">

function fixnumber()
{
var str=prompt("Please enter number");
if (str!=null && str!="")
  {

  var fixed=str.substr(1,10);

  document.getElementById('txt1').value=fixed;

  }
}
</script>

Number TEST: <input name="textbox1" type="text" id开发者_运维问答="txt1"/>

<input name="buttonExecute" onclick="fixnumber(document.getElementById('txt1'))" type="button" value="Enter number" />` 

Change:

document.getElementById('txt1').value=fixed;

To:

$('#txt1').val(fixed);

HTML:

<input type="text" id="txt1" name="textbox1">
<input type="button" id="btn" name="buttonExecute" value="Enter number">

JavaScript:

$('#btn').click(function() {
    var n = prompt('Please enter number');
    if ( n ) {
        $('#txt1').val(n);
    }
});

Live demo: http://jsfiddle.net/simevidas/3vxKW/1/