The <form> element defines how the data will be sent. All of its attributes are designed to let you configure the request to be sent when a user hits a submit button. The two most important attributes are action and method.

action: This attribute defines where the data gets sent. Its value must be a valid URL. If this attribute isn't provided, the data will be sent to the URL of the page containing the form.
method: This attribute defines how data is sent. The HTTP protocol provides several ways to perform a request; the most common of which are the GET method and the POST method.

<form action="/somewhere_else" method="get">

The GET method

The GET method is the method used by the browser to ask the server, if a form is sent using this method the data sent to the server is appended to the URL.

The POST method

The POST method is a little different. It's the method the browser uses to talk to the server, If a form is sent using this method, the data is appended to the body of the HTTP request.

On the server side: retrieving the data

Whichever HTTP method you choose, the server receives a string that will be parsed in order to get the data as a list of key/value pairs. The way you access this list depends on the development platform you use and on any specific frameworks you may be using with it. The technology you use also determines how duplicate keys are handled; often, the most recently received value for a given key is given priority.