javascript code behind values

Question

I have the following JS code which shows/hides buttons (had to be done this way, and please don't say do it another way).

Sys.WebForms.PageRequestManager.getInstance().add_beginRequest(beginRequestHandle);
Sys.WebForms.PageRequestManager.getInstance().add_endRequest(endRequestHandle);
function beginRequestHandle(sender, Args) {
                document.getElementById("ltInstructions").style.visibility = "hidden";
                document.getElementById("btnSubmit").style.visibility = "hidden";
                document.getElementById("btnToExcel").style.visibility = "hidden";
            }
function endRequestHandle(sender, Args) {
                    if(<%=resultsCount %> > 0)
                    {
                        document.getElementById("ltInstructions").style.visibility = "visible";
                        document.getElementById("btnSubmit").style.visibility = "visible";
                        document.getElementById("btnToExcel").style.visibility = "visible";
                    }
                    else
                    {
                        document.getElementById("results").innerHTML = "<br><b><center><font size=20>No results found, please try again.</b></font></center>";
                    }
                }

The problem is <%=resultsCount %> which gets initialized to 0 in the code behind and then later updated in Timer_Tick method. The Js above always picks it up as 0.

How to make the JS pick it up as the correct value?

Adil · Accepted Answer · 2012-07-09 08:54:57Z

1

Use asp:hiddenfield instead and change its value in Timer_Tick, You will get updated value for it.

In HTML

 <asp:HiddenField id="resultsCount" runat="server" Value="String" />

In Javascript

resultsCount = document.getElementById('<%= resultsCount.ClientID %>').value;

answered Jul 9, 2012 at 8:54

Adil

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1 Comment

user1468537 Over a year ago

Thank you. That has fixed it :)

Patrick Oscity · Accepted Answer · 2012-07-09 09:52:43Z

0

Try looking at the source of the webpage in your browser. You have to write the timer in JavaScript, because <%=resultsCount %> is evaluated once only and therefore, all the client sees is

 if (0 > 0) {
   ...
 }

You can implement a timer in JavaScript using the setInterval and clearInterval methods. Define a function update() that should be called whenever something needs to be updated and then do

var updateInterval

function update() {
  if(condition) {
    /* update stuff */
  } else {
    /* no more updates needed */
    clearInterval(updateInterval) /* stop updating */
  }
}

updateInterval = setInterval(update, 1000) /* call update() every 1000 ms, that is every second */

edited Jul 9, 2012 at 9:52

answered Jul 9, 2012 at 8:51

Patrick Oscity

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1 Comment

user1468537 Over a year ago

yes that is correct I do get 0 > 0. How to perform the timer in JS?

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