css3 circular progress meter

HTML

<h1>CSS3 pie graph timer with jquery</h1>

        <p>Credits to <a href="http://atomicnoggin.ca/blog/2010/02/20/pure-css3-pie-charts/" target="_blank">atomicnoggin</a> for original CSS3 pie graph code.</p>

        <p>Changed to em's so you just change the font-size in the timer class and everything will resize accordingly.</p>

        <h2>Size</h2>

        <p><input type="button" id="size" value="Set timer to" /> <input type="text" id="size" size="2" value="40" />px</p>

        <h2>Set percent</h2>

        <p><input type="button" id="percent" value="Set timer to" /> <input type="text" id="percent" size="2" value="35" />%</p>

        <h2>Stop watch</h2>

        <p><input type="button" id="watch" value="Start" /> count down from <input type="text" id="watch" size="2" value="10" /> seconds</p>

        <div class="timer"></div><div class="timer fill"></div>

        <p><a href="http://blakek.us/css3-pie-graph-timer-with-jquery/">Back to discussion</a></p>

CSS

.timer {

                position:relative;

                font-size: 200px;

                width:1em;

                height:1em;

                float: left;

            }

            .timer > .percent {

                position: absolute;

                top: 1.05em;

                left: 0;

                width: 3.33em;

                font-size: 0.3em;

                text-align:center;

            }

            .timer > #slice {

                position:absolute;

                width:1em;

                height:1em;

                clip:rect(0px,1em,1em,0.5em);

            }

            .timer > #slice.gt50 {

                clip:rect(auto, auto, auto, auto);

            }

            .timer > #slice > .pie {

                border: 0.1em solid #c0c0c0;

                position:absolute;

                width:0.8em; /* 1 - (2 * border width) */

                height:0.8em; /* 1 - (2 * border width) */

                clip:rect(0em,0.5em,1em,0em);

                -moz-border-radius:0.5em;

                -webkit-border-radius:0.5em; 

                border-radius:0.5em; 

            }

            .timer > #slice > .pie.fill {

                -moz-transform:rotate(180deg) !important;

                -webkit-transform:rotate(180deg) !important;

                -o-transform:rotate(180deg) !important;

                transform:rotate(180deg) !important;

            }

            .timer.fill > .percent {

                display: none;

            }

            .timer.fill > #slice > .pie {

                border: transparent;

                background-color: green;

                width:1em;

                height:1em;

            }

JavaScript

var timer;

            var timerCurrent;

            var timerFinish;

            var timerSeconds;

            function drawTimer(percent){

                $('div.timer').html('<div class="percent"></div><div id="slice"'+(percent > 50?' class="gt50"':'')+'><div class="pie"></div>'+(percent > 50?'<div class="pie fill"></div>':'')+'</div>');

                var deg = 360/100*percent;

                $('#slice .pie').css({

                    '-moz-transform':'rotate('+deg+'deg)',

                    '-webkit-transform':'rotate('+deg+'deg)',

                    '-o-transform':'rotate('+deg+'deg)',

                    'transform':'rotate('+deg+'deg)'

                });

                $('.percent').html(Math.round(percent)+'%');

            }

            function stopWatch(){

                var seconds = (timerFinish-(new Date().getTime()))/1000;

                if(seconds <= 0){

                    drawTimer(100);

                    clearInterval(timer);

                    $('input[type=button]#watch').val('Start');

                    alert('Finished counting down from '+timerSeconds);

                }else{

                    var percent = 100-((seconds/timerSeconds)*100);

                    drawTimer(percent);

                }

            }

            $(document).ready(function(){

                $('input[type=button]#percent').click(function(e){

                    e.preventDefault();

                    drawTimer($('input[type=text]#percent').val());

                });

                $('input[type=button]#size').click(function(e){

                    e.preventDefault();

                    $('.timer').css('font-size',$('input[type=text]#size').val()+'px');

                });

                $('input[type=button]#watch').click(function(e){

                    e.preventDefault();

                    if($('input[type=button]#watch').val() == 'Start'){

                       ...