HTML form serialization

An HTML form submission is exposed to a server as an HTTP GET or POST request.

When a form is submitted, the browser collects the form data and serializes it:

Serialization is the process whereby a data structure is translated into a format suitable for transfer over a network.

For GET requests

Data:

• is URL-encoded
• and added in the URL's query string as query param(eter)s

Notes:

• the max length of an URL has a de facto limit of 2000 characters
• the exact structure of the query string is not standardized
• the HTTP request body is empty

For POST requests

Data:

• is serialized into the structure specified by the enctype attribute
• and added in the HTTP request body

enctype can be:

• application/x-www-form-urlencoded
• multipart/form-data
• text/plain

Query params

Any HTTP method type may include query params.

When a form is submitted using the POST method to an URL containing query params:

• the query params are sent to the server
• they are separated from the request body
• they should be treated as read-only