using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Threading;

public partial class _Default : System.Web.UI.Page 
{
    protected void Page_Load(object sender,EventArgs e)
    {

         // Identify button as a "disabled-when-clicked" button...
         WebHelpers.DisableButtonOnClick( buttonTest,"showPleaseWait" ); 
    }

    protected void buttonTest_Click( object sender,EventArgs e )
    {
        // Emulate a server-side process to demo the disabled button during
        // postback.
        Thread.Sleep( 5000 );
    }
}



using System;
using System.Web;
using System.Web.UI.WebControls;
using System.Text;

public class WebHelpers
{
    //
    // Disable button with no secondary JavaScript function call.
    //
    public static void DisableButtonOnClick( Button ButtonControl )
    {
        DisableButtonOnClick( ButtonControl,string.Empty );    
    }

    //
    // Disable button with a JavaScript function call.
    //
    public static void DisableButtonOnClick( Button ButtonControl,string ClientFunction )
    {   
        StringBuilder sb = new StringBuilder( 128 );

        // If the page has ASP.NET validators on it,this code ensures the
        // page validates before continuing.
        sb.Append( "if ( typeof( Page_ClientValidate ) == 'function' ) { " );
        sb.Append( "if ( ! Page_ClientValidate() ) { return false; } } " );

        // Disable this button.
        sb.Append( "this.disabled = true;" ); 

        // If a secondary JavaScript function has been provided,and if it can be found,// call it. Note the name of the JavaScript function to call should be passed without
        // parens.
        if ( ! String.IsNullOrEmpty( ClientFunction ) ) 
        {
            sb.AppendFormat( "if ( typeof( {0} ) == 'function' ) {{ {0}() }};",ClientFunction );  
        }

        // GetPostBackEventReference() obtains a reference to a client-side script function 
        // that causes the server to post back to the page (ie this causes the server-side part 
        // of the "click" to be performed).
        sb.Append( ButtonControl.Page.ClientScript.GetPostBackEventReference( ButtonControl ) + ";" );

        // Add the JavaScript created a code to be executed when the button is clicked.
        ButtonControl.Attributes.Add( "onclick",sb.ToString() );
    }
}