Robot Speed Calculator

<script type="text/javascript">
// <![CDATA[
    $("input:enabled").change(function() {
            calcValues();
        });
        function calcValues () {
            var rpm = $("input[name='rpm']").val();
            var ratio = $("input[name='ratio']").val();
            var cir = $("input[name='diameter']").val() * Math.PI;
            var ipm = rpm * ratio * cir;
            var fpm = ipm / 12.0;
            var mph = fpm * 60 / 5280;
            var mpm = fpm * 0.3048;
            var kph = mpm * 60 / 1000;
            $("input[name='circ']").val(cir.toFixed(2));
            $("input[name='speedIPM']").val(ipm.toFixed(2));
            $("input[name='speedFPM']").val(fpm.toFixed(2));
            $("input[name='speedMPH']").val(mph.toFixed(2));
            $("input[name='speedMPM']").val(mpm.toFixed(2));
            $("input[name='speedKPH']").val(kph.toFixed(2));
        }
        $(function() {
            calcValues();
        });
    // ]]>
    </script>