Lecture 6 - Applications #3.2: HTTP

Submission Methods

The two ways in which form data can be returned to the server are METHOD=GET and METHOD=POST.

GET: This method is (according to the original specification) preferred if the submission of the form is not going to have a lasting effect on the global state of the universe -- that is, it does not have side effects. For example, it may query a database, returning the result as HTML. A HTTP GET request is issued to the ACTION URL specified in the <FORM> markup tag, with the urlencoded form information appended after a separating "?" character. This can generate very long URLs.
POST: This method was originally used where processing of the form was intended to have side effects, eg, updating the contents of a database. In this case, a HTTP POST transaction is performed. The "body" of the transaction contains the urlencoded form data, as a single long line of text. The POST transaction is directed at the URL specified in the ACTION attribute of the <FORM> tag.

In "real life", GET and POST methods are used pretty much interchangeably, depending on the programmer's or system designer's preference.

Lecture 06: Applications #3.2: HTTP