HTML forms provide three methods of encoding.
The specifics of the formats don’t matter to most developers. The important points are:
When you are writing client-side code, all you need to know is use
multipart/form-data when your form includes any
<input type="file"> elements.
When you are writing server-side code: Use a prewritten form handling library (e.g. Perl’s
CGI->paramor the one exposed by PHP’s
$_POST superglobal) and it will take care of the differences for you. Don’t bother trying to parse the raw input received by the server.