HTTP, or Hypertext Transfer Protocol, is the method through which web page requests are sent to a server. It is used worldwide, on every web browser, and is essential for the function of the World Wide Web.
Using HTTP is simple from a user's perspective. All the user has to do is type in a web address and press enter.
Sending a Request
What happens behind the scenes is a little more complicated. After a web address is typed in, the browser asks a DNS (Domain Name Server) for the numerical IP address of the server, and then sends a request to that server.
Sending a request evokes a very specific response from the server, depending on the request that is sent. Most commonly, a request from a browser is asking for the content the server is hosting, typically a web page, which the server will now send.
Types of Requests
The most common request is a GET, what is sent when a browser asks for content. Also common is POST, the request sent when a browser wants to send data to the server (such as the content of a form that a user has filled out.
Using a website that requires heightened security, such as an online banking site, requires the use of a special version of HTTP, called HTTPS. HTTPS (Hypertext Transfer Protocol Secure) encrypts the requests and response from a server, making them undecipherable to third parties.