<HTML>
<HEAD>
[removed]
var timerID;
function window_onload()
{
timerID = setTimeout("alert('计时结束!')",30000);
alert("计时开始\n(3秒种)");
}
function butStopTimer_onclick()
{
clearTimeout(timerID);
alert("计时被清除");
}
[removed]
</HEAD>
<BODY LANGUAGE = JavaScript
<FORM NAME=form1>
<INPUT TYPE="button" VALUE="清除计时" NAME=butStopTimer LANGUAGE=JavaScript
butStopTimer_onclick()">
</FORM>
</BODY>
</HTML>