Calling server side methods from client side (javascript)

HTTP handlers and HTTP Modules

Built-In HTTPHandlers:

HttpHandler	Purpose
PageHandlerFactory	Processes .aspx pages.
WebServiceHandlerFactory	Processes .asmx XML Web services.
HttpForbiddenHandler	Yields an error message indicating that a type of page is not in service. By default all .asax, .vb, .cs, .ascx, .config, .csproj, .vbproj, .webinfo files are mapped to this in machine.config.
StaticFileHandler	Delivers any page that isn't specifically mapped, such as .html, .htm, and .jpg.
TraceHandler	Shows the page containing all of the trace output.

To get membership database in SQL Server

Type the following in VSTS command prompt:
aspnet_regsql.exe -E -S -d -A all

Creating and Managing Profiles

Sending special characters in Querystring

When you need to pass some special charaters(+, % etc.) in Querystring you will need to encode it first before redirecting.

Response.Redirect(www.abc.com/createtask.aspx?taskID= + Server.UrlEncode(Session["TaskGUID"].ToString())

This is very helpful when you are going to send some GUID values.
But keep in mind don't use Server.UrlDecode in createTask.aspx page as Request.Querystring automatically recieves decoded string.

Global.ASAX Error handler to know which file is missing

Write the following code in your Global Error handler to know which file is missing.
void Application_Error(object sender, EventArgs e)
{
String FileName = HttpContext.Current.Request.Url.ToString();
String RequestFrom = HttpContext.Current.Request.UrlReferrer.ToString();.....
}

Put a breakpoint at first line and check the value of FileName to know which file is missing.