要完成此效果需要两个步骤 第一步：把如下代码加入到区域中 <script language="JavaScript"> function showMilitaryTime() { if (document.form.showMilitary[0].checked) { return true; } return false; } function showTheHours(theHour) { if (showMilitaryTime() || (theHour > 0 && theHour < 13)) { if (theHour == "0") theHour = 12; return (theHour); } if (theHour == 0) { return (12); } return (theHour-12); } function showZeroFilled(inValue) { if (inValue > 9) { return "" + inValue; } return "0" + inValue; } function showAmPm() { if (showMilitaryTime()) { return (""); } if (now.getHours() < 12) { return (" am"); } return (" pm"); } function showTheTime() { now = new Date document.form.showTime.value = showTheHours(now.getHours()) + ":" + showZeroFilled(now.getMinutes()) + ":" + showZeroFilled(now.getSeconds()) + showAmPm() setTimeout("showTheTime()",1000) } </script>

24小时制
12小时制

第二步：把“onload=showTheTime()”加在标记里 例如：