What is ashx in ASP.NET

What is ashx ? HTTP Generic handler

A handler is responsible for requests from a browser.  It is a class that implements the IHttpHandler interface.

A webforms page, aspx file,  is a another class with IHttpHandler interface.

namespace System.Web.UI

{

    public class Page : TemplateControl, IHttpHandler

Handler can be called by by file extension or directly.

Only one handler can be called per request.

Reference:

Call ASP.NET Handler (ASHX) by JavaScript

http://rayaspnet.blogspot.com/2011/04/call-aspnet-handler-ashx-using.html