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Sam OZFlag for Australia

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ASP.NET trigger javascript function from Server side

hi Experts,



  On the click of a button , some server side process is happening  .  I already have a small piece of javascript ( runs at on clientclick) to show a  'waiting image'  .
    The javascript line of code is
            document.getElementById("HiddenLoadingImage").style.display = 'block';
    (The defualt display state of the Image is hidden  and it is shows up only when the button is clicked)

 Also, when the server  processing is over, I have a  server side line of code to show a message that the processing is done
   
    System.Web.HttpContext.Current.Response.Write( _
           "<SCRIPT LANGUAGE='JavaScript'> alert('Process Done')</SCRIPT>")
     
    But my issue is -  The Waiting image  is still visible when the Alert of  "Process Done"  pops up.  
    How can I  hide the image first and then show the Alert ?

  Thanks

   Sam
Avatar of Ramkisan Jagtap
Ramkisan Jagtap
Flag of Finland image

Please check the default state of the image. I doubt if it is hidden when it is loaded.

or you can try editing your server side script as below:

 System.Web.HttpContext.Current.Response.Write( _
           "<SCRIPT LANGUAGE='JavaScript'> alert('Process Done');
document.getElementById("HiddenLoadingImage").style.display = 'none';     </SCRIPT>")
Avatar of Sam OZ

ASKER

Hi Ramkisan,

     I am not sure I stated my issue clearly . When the alert pops up the image is visible. But if I click ok, the image becomes invisible

 I already tired the code you suggested . It doesn't work , unfortunately
HI Sam,

Just give a try with following:

System.Web.HttpContext.Current.Response.Write( _
            "<SCRIPT type='text/javascript'>  document.getElementById("HiddenLoadingImage").style.display = 'none';
alert('Process Done');
    </SCRIPT>")
Avatar of Sam OZ

ASKER

Hi Ram,

   I have tried that too,  That is not the solution.
If possible, Can you please post your code here?
Avatar of Sam OZ

ASKER

Hi Ram,

   Please see the attachment for the test code . ( You need to have an image by name Spinner.jpg  under the folder \images  )

 Just a correction  in my code ---  
      Use either    System.Web.HttpContext.Current.Response.Write
            or  ScriptManager.RegisterStartupScript
       ( You need to comment out one of thse)
ClientPostFromServer.zip
Hello Sam,

Change you code as below:

<html xmlns="http://www.w3.org/1999/xhtml">

<head id="Head1" runat="server">
   
   <script type="text/javascript" language="javascript">

       function AlertClient() {
           document.getElementById("HiddenLoadingImage").style.display = 'none';
           alert("Test Done");
       }

       function DisplayLoadingImage() {
           document.getElementById("HiddenLoadingImage").style.display = "block";
       }

  </script>

    <title></title>
</head>

<body onload="AlertClient()">
    <form id="form1" runat="server">
         <div>      
        <img id='HiddenLoadingImage' src="Images/Spinner.jpg" style="display:none"/>
        <asp:Button ID="Button1" runat="server" Text="Button" OnClientClick="DisplayLoadingImage()" />
    </div>        
    </form>
</body>
</html>

 Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
        WasteTime()
        Dim strMessage As String
        strMessage = "This is test"
    End Sub

    Sub WasteTime()
        Dim i, j, k As Integer
        For i = 0 To 1000
            For j = 0 To 1000
                For k = 0 To 100

                Next
            Next
        Next
    End Sub
Avatar of Sam OZ

ASKER

Hi Ram,

    It can't happen on the Onload in the client . it should happen only after the Button is clicked ( In my actual code there are many other controls)

 Also , Infact, strictly speaking , the Alert should come with the value of a server variable ( But that is not the real problem I face)
ASKER CERTIFIED SOLUTION
Avatar of Ramkisan Jagtap
Ramkisan Jagtap
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Avatar of Sam OZ

ASKER

Hi Ram & other Experts,

    AJAX is not used in this project , unfortunately  ( This is a revamp project ) . Also I am a little naive with AJAX

    Is there really a way to do this with no AJAX ?