Question

I am calling a javascript function to return yes,no values from the user in a button click event inside an update panel. I want to call certain server side functions depending on user action (yes/no). My javascript code is given below

function Confirm() {
        var confirm_value = document.createElement("INPUT");
        confirm_value.type = "hidden";
        confirm_value.name = "confirm_value";
        if (confirm("Do you want to save data?")) {
            confirm_value.value = "Yes";
        } else {
            confirm_value.value = "No";
        }
        document.forms[0].appendChild(confirm_value);
    }

I am calling this in my server side button click which is shown below.

 if ((Convert.ToInt32(_dsLeaveDetails.Tables[0].Rows[0][0]) == 1) 
            {

                ShowAlert("Leave is already marked for this date");
                return;

            }
            else if ((Convert.ToInt32(_dsAttendanceDetails.Tables[0].Rows[0][0]) >= 1)) 
            {

                ScriptManager.RegisterStartupScript(this, this.GetType(), "alert", "Confirm();", true);
                string confirmValue = Request.Form["confirm_value"];
                if (confirmValue == "Yes")
                {
                      ScriptManager.RegisterStartupScript(this, this.GetType(), "alert", "alert('You clicked YES!');", true);
                }
                else
                {
                  ScriptManager.RegisterStartupScript(this, this.GetType(), "alert", "alert('You clicked YES!');", true);
                }


                return;
            }

The issue is, pop up is showing only after the code is fully executed and because of that user action (yes/no) cannot be processed further.
Also I cannot call javascript function on clientclick event because immediately I dont require a pop up. Only after checking the dataset dsAttendanceDetails, I need the pop up. Kindly help.

Answer 1

You seems to assume that the line ScriptManager.RegisterStartupScript(this, this.GetType(), "alert", "Confirm();", true); would execute the java-script function immediately – but that’s simply not possible. This call would execute the JS function when response reaches to the client i.e. when subsequent server code would have been already executed.

The java-script function would be executed at the client side and you will need a form submit (sync or asynchronous does not matter) to retrieve the user’s choice at the server side. So you need to two requests – first would register the script that would confirm user choice and subsequent request to send the user’s choice to the server.