Hypertext Transfer Protocol (HTTP)

The Hypertext Transfer Protocol (HTTP) is the protocol used over TCP/IP to carry requests and responses between a Web server and a Web client. It can be said that HTTP is to the Web what TCP/IP is to the Internet.
Note: HTTP is not a secure protocol. There are, however, a couple of variations of HTTP that provide for encrypted transmission. These variations include the Secure Hypertext Transfer Protocol (SHTTP) and Hypertext Transfer Protocol Secure (HTTPS).
HTTP is a stateless protocol, which means that it cannot remember what occurred previously. (Programs that are stateful can remember what happened the last time the program was run and keep track of various configuration settings.)
HTTP uses a series of requests and responses to transfer data. Basically, the client sends a request, and the server responds to the request. This transfer of data on the Web, using HTTP, usually occurs in the following four stages:

1. Connection—The client connects to the Web server.
2. Request—The client sends a resource request message to the server.
3. Response—The server delivers a response to the client.
4. Close—The connection is closed between the client and the server.
Note: Under the original HTTP specifications, the connection closes after the server response. However, a newer version of HTTP introduces persistent connections; this version maintains the connection and continues to exchange multiple requests until the connection is explicitly closed.
In addition to HTTP, another Web standard called Hypertext Markup Language (HTML) plays a crucial role in the Web's functionality. After the client makes its request and the server responds, the client uses a Web browser to interpret and display the information