An ALX file is an ActiveX file that is embedded in Web pages in the form of HTML components. ActiveX controls were formally known as OLE controls or OCXs. ALX files can be used to insert a variety of functionalities in a web page such adding a timer control for updating the page’s content periodically, or add a Popup window control for displaying tooltip-style help based on user action. ALX files care linked using tag within HTML code of a web page. You can open ALX files in Microsoft Internet Explore, Microsoft ActiveX Control Pad, and text editors such as Notepad and Notepad++.
ALX File Format - More Informaiton
ALX files are in plain text file format and can be edited by opening these in a text editor. ActiveX controls can be included in a web page by dropping onto web page. However, in order to build dynamic web pages, the controls are integrated together with the help of JScript. Controls on a web page are associated with the events and values of the controls, thus giving complete control for user interactions.