<body>
  <div id="timerDiv">
    <input type="button" id="btnStart" value="Start"
           onclick="btnStartClick();" />
    <input type="button" id="btnStop" value="Stop"
           onclick="btnStopClick();" />
    <input type="button" id="btnReset" value="Reset"
           onclick="btnResetClick();" />    
    <input type="text" readonly="readonly" id="tf1" size="6"
           style="text-align:center;" />
  </div>
</body>