计时器功能按钮

<div class="ctrls">
    <a class="" href="#start" id="start">开始</a>
    <a href="#stop" id="stop" class="hide">停止</a>
    <a href="#reset" id="reset" class="">重置</a>
    <a class="hide" href="#lap" id="lap">计时</a>
</div>

var graph = {
    'state': {
        'pause': false,
        'inUse': false,
        'lapNum': 1
    },
    'markerStyle': {
        'green': '#67d276',
        'red': '#f73748'
    },
    'coords': {
        'x': 5,
        'y': 50,
        'prev': {
            'x': 0,
            'y': 60
        }
    },
    'msc': {
        'fastestLap': 0,
        'slowestLap': 99999999,
        'startTime': 0
    }
};

//表盘元素
var lap_mil = document.getElementById('lap_mil'),
        lap_sec = document.getElementById('lap_sec'),
        lap_min = document.getElementById('lap_min'),
        timer_mil = document.getElementById('timer_mil'),
        timer_sec = document.getElementById('timer_sec'),
        timer_min = document.getElementById('timer_min'),
        watch = document.getElementById('watch'),
        avg_time = document.getElementById('avg_time');

//图形元素
var canvas = document.getElementById('graph'),
        ctx = canvas.getContext('2d'),
        lap = document.getElementById('lap'),
        lap_numbers = document.getElementById('lap_numbers');