Web page that can be used as a component by other Web pages; for example, a navigation bar called "navbar.ascx" might be referenced by all pages within a ASP-driven website; a single change to the navbar.ascx file will change the navigation bar in all the other pages.
Program(s) that open ascx files
Windows: Microsoft ASP.NET
Information from FileInfo.com - The File Extensions Resource.
http://www.fileinfo.com/extension/ascx
