页面脚本代码：

 <script type="text/javascript">

        //timer操作函数

        var CallTimeLen = "0";

        var timestart = null;

        var timer = null;

        //重新计时

        function Reset() {

            timestart = new Date();

            document.getElementById("showTime").innerHTML = "00:00";

        }

        //计时 开始

        function StartCal() {

            var timeend = new Date();

            var timedifference = timeend.getTime() - timestart.getTime();

            timeend.setTime(timedifference);

            var minutes_passed = timeend.getMinutes();

            if (minutes_passed < 10) {

                minutes_passed = "0" + minutes_passed;

            }

            var seconds_passed = timeend.getSeconds();

            if (seconds_passed < 10) {

                seconds_passed = "0" + seconds_passed;

            }

            document.getElementById("showTime").innerHTML = minutes_passed + ":" + seconds_passed;

 

            window.timer = window.setTimeout("StartCal();", 1000);

         

        }

       

    </script>

 

aspx页面：

    <span id="showTime" style="color: Red">00:00</span>

 

aspx.cs代码：

     只需在需要调用计时函数的事件中加入这句代码就万事俱备，只欠东风：

      ScriptManager.RegisterStartupScript(this, this.GetType(), "js", " var timestart = new Date(); StartCal();", true);

     在需要调用重新计时函数的事件中加入这句代码就大功告成：

      ScriptManager.RegisterStartupScript(this, this.GetType(), "js", " Reset(); StartCal();", true);