javascript系統時間設置操作示例

<script>
 //myTime typeof //object
 window.onload = function() {
 var obody = document.body;
 //設置一個定時器，每過一秒鐘，自動加一秒
 setInterval(fnTime, 1000)
 //如果不執行這個函數，第一次打開時，會過一秒鐘才出來
 fnTime();
 function fnTime() {
 var myTime = new Date();
 var iYear = myTime.getFullYear();
 var iMonth = myTime.getMonth() + 1;
 var iDate = myTime.getDate();
 var iWeek = myTime.getDay();
 var iHours = myTime.getHours();
 var iMinutes = myTime.getMinutes();
 var iSeconds = myTime.getSeconds();
 var str = "";
 if(iWeek === 0) iWeek = "星期日"
 if(iWeek === 1) iWeek = "星期一"
 if(iWeek === 2) iWeek = "星期二"
 if(iWeek === 3) iWeek = "星期三"
 if(iWeek === 4) iWeek = "星期四"
 if(iWeek === 5) iWeek = "星期五"
 if(iWeek === 6) iWeek = "星期六"
 str = iYear + "年" + iMonth + "月" + iDate + "日 " + iWeek + " " + toTwo(iHours) + "時" + toTwo(iMinutes) + "分" + toTwo(iSeconds) + "秒"
 obody.innerHTML = str;
 }
 console.log(toTwo(05))//05
 console.log(toTwo(15))//15
 //這個函數主要是讓:時分秒到59秒時，再走一秒就變成了0，而不是00，所以要轉換一下
 function toTwo(n) {
 /*
 if(n < 10) {
 return "0" + n;
 } else {
 return "" + n;
 }
 */
 //我們可以用三目
 return n < 10 ? "0" + n : "" + n
 }
 }
</script>