<html>
<head><script type="text/javascript">var c=0var tfunction timedCount(){ document.getElementById('txt').value=cc=c+1t=setTimeout("timedCount()",1000)}function stopCount()
{ c=0;setTimeout("document.getElementById('txt').value=0",0);clearTimeout(t);}</script></head><body>
<form>
<input type="button" value="开始计时！" onClick="timedCount()"><input type="text" id="txt"><input type="button" value="停止计时！" onClick="stopCount()"></form><p>请点击上面的“开始计时”按钮来启动计时器。输入框会一直进行计时，从 0 开始。点击“停止计时”按钮可以终止计时，并将计数重置为 0。</p>
</body>
</html>