jquery replace an ID with variable

I have an id="test" and would like to have it replaced by the variable:PitchesRemaining: http://jsfiddle.net/xtian/G7Qdp/

HTML:

    <div class="wrap wrap-widgets relative">
        <div class="speedometer" id="test">6</div>
        <span id="AveragePitches">55</span>
        <span id="PitchesToday">15</span>
    </div>

Jquery:

        $(function(){
        var AveragePitches = parseInt($("#AveragePitches").text());
        var Buffer = AveragePitches * .2;
        var PitchesMax = AveragePitches + Buffer;
        var PitchesToday = parseInt($("#PitchesToday").text());
        var PitchesRemaining = PitchesMax - PitchesToday;

        $("#test").change(function() {
        开发者_如何转开发    PitchesRemaining = $(this).val();
            }).change();
    });

You can just change the Id using jQuery's attr method:

obj.attr("id", PitchesRemaining);

I'm not sure what you're trying to do though. If you're trying to use the ID to track a variable, then perhaps you should take a look at .data instead.

EDIT:

After reading your comment in the question; to change the text of the div to the value of PitchesRemaining, just use text:

$("#test").text(PitchesRemaining);

Or html:

$("#test").html(PitchesRemaining);

To change the value of a <div> do this:

$('#test').html(PitchesRemaining);

Note: .change() events are only for input elements, not for divs.