Forms - HTML and XHTML: The Definitive Guide - page 558

change how the parameters get encoded for secure transmission over
the network.
9.2.1. The action Attribute
The required action attribute for the <form> tag gives the URL of the
application that is to receive and process the form's data. Most web-
masters keep their forms-processing applications in a special directory
on their web server, usually named cgi-bin , which stands for Common
Gateway Interface-binaries. [*] Keeping these special forms-processing
programs and applications in one directory makes it easier to manage
and secure the server.
[*] The Common Gateway Interface (CGI) defines the protocol by which servers interact with programs
that process form data.
A typical <form> tag with the action attribute looks like this:
<form action="http://www.kumquat.com/cgi-bin/update">
...
</form>
The example URL tells the browser to contact the web server named www
in the kumquat.com domain and pass along the user's form values to the
application named update located in the cgi-bin directory.
In general, if you see a URL that references a document in a directory
named cgi-bin , you can be pretty sure that the document is actually an
application that dynamically creates the desired page each time it's in-
voked.
9.2.2. The enctype Attribute
The browser specially encodes the form's data before passing that data
to the server so that it does not become scrambled or corrupted during