Ever wonder why some websites have extensions like .htm, .html, .asp, and so on?

Here are a few examples of common web page extensions across various URLs:

When the web was first established, it mainly ran on UNIX systems, and all pages had the .html extension. However, when PCs running DOS or Windows became Web servers, the 8.3 naming rule only allowed three letters for file extensions. This led to two common extensions: .html and .htm. Initially, you could tell if a site was using UNIX or Windows by the file extension, but that distinction no longer exists. For example, Mytour uses a UNIX server but opts for .htm as the extension – it's simply a choice made by the webmaster.

Pages ending in shtml indicate that "Server Side Includes" (SSI) are being used. Unlike static htm and html pages, where the content is directly sent from the server to the client, SSI allows a page to contain placeholders for other files. The server processes these placeholders, inserts the necessary content, and sends the completed page to the client. This technique simplifies updating shared elements like headers and footers across an entire website.

Active Server Pages (asp) is a Microsoft technology that offers enhanced flexibility. A web page can include Visual Basic code, which the server runs when it loads the page. This code can do almost anything — from accessing databases to executing other programs, and customizing pages based on the user’s ID. While this opens up many possibilities, it also introduces the risk of bugs in the code, which may cause the page to "crash." With greater power comes greater responsibility...

It’s now common to encounter jsp and php extensions as well. JSP is one of the latest additions to the Java Enterprise API suite and stands for "Java Server Pages." Essentially, it’s Java's version of ASP, where the embedded code is written in Java rather than Visual Basic. Meanwhile, "PHP" used to stand for "Personal Home Page," but today it refers to "PHP," a scripting language predominantly used with Linux systems.

The pl extension is associated with PERL, a scripting language. Pages using this extension are composed entirely of PERL code, which dynamically generates the content. Similar to ASP pages, the script can execute various tasks depending on the specific requirements of the page.

The cgi extension indicates that a page contains server-executed code, which can vary in type. At Mytour, C++ code is compiled to produce "cgi" files (See How CGI Scripting Works.)

These links will help you learn more: