51help TIY
码：
<html> <body> <input type="text" id="clock" size="35" /> <script language=javascript> var int=self.setInterval("clock()",50) function clock() { var t=new Date() document.getElementById("clock").value=t } </script> <button onclick="int=window.clearInterval(int)">Stop interval</button> </body> </html>
查看结果: