时间精确计算程序

下面为效果显示

脚本说明:
把如下代码加入<body>区域中
<script language="Javascript">
<!-- Gracefully hide from old browsers
function timestamp_class(this_current_time, this_start_time, this_end_time, this_time_difference) { 
		this.this_current_time = this_current_time;
		this.this_start_time = this_start_time;
		this.this_end_time = this_end_time;
		this.this_time_difference = this_time_difference;
		this.GetCurrentTime = GetCurrentTime;
		this.StartTiming = StartTiming;
		this.EndTiming = EndTiming;
	}

//Get current time from date timestamp
	function GetCurrentTime() {
	var my_current_timestamp;
		my_current_timestamp = new Date();		//stamp current date & time
		return my_current_timestamp.getTime();
		}

//Stamp current time as start time and reset display textbox
	function StartTiming() {
		this.this_start_time = GetCurrentTime();	//stamp current time
		document.TimeDisplayForm.TimeDisplayBox.value = 0;	//init textbox display to zero
		}

//Stamp current time as stop time, compute elapsed time difference and display in textbox
	function EndTiming() {
		this.this_end_time = GetCurrentTime();		//stamp current time
		this.this_time_difference = (this.this_end_time - this.this_start_time) / 1000;	//compute elapsed time
		document.TimeDisplayForm.TimeDisplayBox.value = this.this_time_difference;	//set elapsed time in display box
		}

var time_object = new timestamp_class(0, 0, 0, 0);	//create new time object and initialize it

//-->
</script>
<form>
  		<input type="button" value="开始" onClick="time_object.StartTiming()"; name="StartButton">
  </form>
  <form>
  		<input type="button" value="结束" onClick="time_object.EndTiming()"; name="EndButton">
  </form>
  <form name="TimeDisplayForm">
 经过了:
  <input type="text" name="TimeDisplayBox" size="6">
秒
  </form>