如何在特定时间从javascript调用C＃中的函数

Question

<script type="text/javascript">
   var startTime = new Date();
   var TimeTaken;
        //Start the clock!
   window.onbeforeunload = function ()        
   {
       var endTime = new Date();
       //Get the current time.
       var timeSpent = (endTime - startTime);
       seconds = (timeSpent / 1000) % 60;
       TimeTaken = parseInt(seconds);
       //return TimeTaken;
       var temp = document.getElementById('<%=Label1.ClientID %>').value;
       temp = TimeTaken;
       alert(temp);
         <%PageO(); %>
  };

The above JS file runs when I close the tab/page in browser. But the function Which I called <%PageO(); %> <%PageO(); %> executes when the programs starts running itself. This function call in code behind(C#) should execute only when the tab/page is closed not at the start of the program.

Any mistakes in this code?

Answer 1

Try This - You have to use PageMethods

<script type="text/javascript">
var startTime = new Date();
   var TimeTaken;
        //Start the clock!
   window.onbeforeunload = function ()        
   {
       var endTime = new Date();
       //Get the current time.
       var timeSpent = (endTime - startTime);
       seconds = (timeSpent / 1000) % 60;
       TimeTaken = parseInt(seconds);
       //return TimeTaken;
       var temp = document.getElementById('<%=Label1.ClientID %>').value;
       temp = TimeTaken;
       alert(temp);
       // USE PAGEMETHODS FOR CODE BEHIND METHOD CALL
         PageMethods.PageO(function (response) {                 
        alert(response);
    });
  };
</script>

• And you have to add ScriptManager in your .aspx page as below

<asp:ScriptManager ID="ScriptManager1" runat="server" EnablePageMethods="true">

• And in .aspx.cs file your Method with WebMethod as below

  `

  [System.Web.Services.WebMethod]

   public static string PageO() { return "Yes this is working"; } 

  `