http:// definition

HTTP

The Hypertext Transfer Protocol (HTTP, http) is the basic, underlying, application-level protocol used to facilitate the transmission of data to and from Web server. HTTP provides a simple, fast way to specify the interaction between client and server. The protocol actually defines how a client must ask for data from the server and how the server returns it. HTTP does not specify how data actually transferred; this is up to lower-level network protocols such as TCP.
The first version of HTTP, known as version 0.9, was used as early as 1990. HTTP version 1.0 as defined by RFC 1945, is supported by most servers and clients (Web browsers). However, HTTP 1.0 does not properly handle the effects of hierarchical proxies and caching, or provide features to facilitate virtual hosts. More important HTTP 1.0 has significant performance problems due to the opening and closing of many connections for a single Web page.
The current version HTTP 1.1 solves many of the past problems of the protocol. It is supported by version 4-generation Web browsers and up. There still many limitations to HTTP however, it is used increasingly in applications that need more sophisticated features, including distributed authoring, collaboration, multimedia support, and remote procedure calls. Various ideas to extend HTTP have been discussed and generic Extension Framework for HTTP has been introduced by the W3C Already, some facilities such as client capability detection and privacy negotiation between browser and server have implemented on top of HTTP, but most of these protocols are still being worked out. For now, HTTP continues to be fairly simple, so this discussion will focus on HTTP 1.0 and 1.1.