if (!this.Page.IsClientScriptBlockRegistered("hideMessage"))

{ this.Page.RegisterStartupScript("hideMessage", 

	"<script>document.getElementById('" + pnlMessage.ClientID + "').style.display = 

				 'none'</script>;"); }

To call a Web.Config appSettings entry from the ASP.NET XML Desinger (not the code behind) then,

call "<%$ appSettings:WEB_SERVICE_URL_SEARCH %>"

or

"<%$ connectionString:DATABASE_CONNECTION_STRING_NAME %>".  

Examples 

<asp:Button ID="btnNewSearch" runat="server" OnClientClick="javascript:location.reload();" Text="New Search" />

or

<input type="button" value="Reload Page" onClick="window.location.reload()">

<input type="button" value="Reload Page" onClick="history.go(0)">

<input type="button" value="Reload Page" onClick="window.location.href">
 

protected override void OnInit(EventArgs e)

{

    btnSearch.Attributes.Add("onclick", "javascript:" + btnSearch.ClientID + ".disabled=true;" 

			+ this.Page.GetPostBackEventReference(btnSearch));

    base.OnInit(e);

}

or

Disable ASP Button on Submit and capture the PostBack OnClick Event

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2. Error Handling in ASP.Net Ajax Applications
3. Handling exceptions in ASP.NET Ajax
4. Asp.net Ajax Exception Logging
5. How to improve ASP.NET AJAX error handling
6. Asynchronous error handling change in ASP.NET AJAX 3.5
7. ScriptManager - AsyncPostBackErrorMessage Property
8. Tip/Trick: Handling Errors with the UpdatePanel control using ASP.NET AJAX
9. Error Handling in ASP.NET
10. Sys.WebForms.PageRequestManagerParserErrorException - what it is and how to avoid it
11. Configuring Visual Studio to Debug .NET Framework Source Code
12. ELMAH: Error Logging Modules and Handlers for ASP.NET (and MVC too!)

public static T FindControl<T>(this Control control, string controlId) where T : Control

{

    return (T)control.FindControl(controlId);

}

1) Insert your ConnectionString in a text file called Connection.config or any other name.

2) In your Web.Config file, reference the Connection.config file as below:

    <connectionStrings configSource="Connection.config" />.

That's it. 

1)    char[] delimiterChars = { ':'};
       string[] args = t.Split(delimiterChars);

2)    string[] args = t.Split(new char[] {':'});