.aspx: The file extension of Web page.
webpage provides a graphical user interface (text, images, buttons, etc.), using which you can design the page which will be rendered to user on browser

.ascx: The file name extension for the user control.
User controls works as containers into which you can put markup and Web server controls. You can reuse this user control as a normal control across the application in web pages (.aspx files)

.asmx: The file extension of web service page.
web service does not provide a graphical user interface. It is mainly used to fetch data and perform actions.

hi sir,
i m hrishabh,
sir can we use web service on aspx page also? and why use aspx?