set variable from text entered in a text box

Hi. I have 2 text boxes in a form the user can type numbers into. I just want to add the numbers they type in together and output the answer. I'm starting off simple and will get more complicated with my calculations later. I actually have the calculations working if they are entered into a database, but we need this to work on the fly depending on what the user typed into the text boxes.

I am only able to set the text box values and output them, but I cannot get them to add together. I have some javascript that outputs what was typed into the boxes by using CFSet. Is this the way I should write this? Is there a way to condense the javascript, or do I need to separate each set of text box code out? Is there a different way to do this simple calculation with just Cold Fusion, or do I need the javascript to grab the numbers that are entered into the text boxes? Here's the code I have below. If you remove the CFset price and the output of Price, you'll see that this code outputs the X and Y text boxes. Thanks for your help.

<cfparam name="url.X" default="">

<cfparam name="url.Y" default="">

<cfoutput>

<script type="text/javascript">

        var pageSubmit = '#jsStringFormat(url.X)#';

        function appenX(){

            document.getElementById('submitLink').href = '?X=' +

            encodeURIComponent(

            (pageSubmit.length?pageSubmit + ', ':'') +

                document.getElementById('X').value);

        }

  var pageSubmit = '#jsStringFormat(url.Y)#';

        function appenY(){

            document.getElementById('submitLink').href = '?Y=' +

            encodeURIComponent(

            (pageSubmit.length?pageSubmit + ', ':'') +

                document.getElementById('Y').value);

        }

    </script>

    <cfform name="theForm" action="##" method="get">

        <cfinput type ="text" name="X" id="X" value=""><br />

        <cfinput type ="text" name="Y" id="Y" value="">

        <input type="submit" id="submitLink" onclick="appenX();" onclick="appenY();" value="Update">

    </cfform>

    <cfset X = #url.X#>

    <cfset Y = #url.Y#>

    <cfset Price = X + Y>

    #X#<br />

    #Y#

    #Price#

</cfoutput>

Andy