What happens when a web page request is for a directory?
Different Web Servers handle this in slightly different ways.
Apache Web Server
It would appear in a specific web server's configuration file like:
DirectoryIndex index.htm index.html index.php
Microsoft Internet Information Server
Similarly, the Microsoft Internet Information Server (IIS) has a configuration property panel called Documents and you can specify the list of files, and the order the web server should search for them:
The web server will search within the requested directory for the available files. For IIS, the search for the files is case-insensitive. That is, "default.htm" or "DeFaUlT.HTM" would be loaded, regardless of the capitalization.
If a file is found, then it is served for that request.
If no file is found, the web server will either server an error page such as 404 Page Not Found, or alternatively, show a directory listing of all of the files in that directory.