Hypertext Transfer Protocol (HTTP)
The Hypertext Transfer Protocol (HTTP) is a protocol originally designed in the early 1990s at CERN in order to enable information to be easily shared between people over an IP network.
HTTP was quickly adopted by the world, as it made creating and sharing information significantly simpler than any protocol that had been created up to that date.
HTTP is used in all web browsers to allow users to access web sites. Originally, web paged were written using a very simple HTML. However, HTTP enables one to access not only HTML pages, but also graphics, music, interactive games, and so on. Indeed, HTTP is a transport protocol that defines how a "user agent" (the more accurate term for a browser) accesses information on the Internet, but it does not impose a restriction on what that information might be.
A typical HTTP request might look like this:
GET / HTTP/1.1
User-Agent: MyUserAgent
Host: www.techabulary.com
Accept: */*
And, a tyical response might look like this (the HTML was removed for brevity):
HTTP/1.1 200 OK
Date: Sun, 23 Mar 2008 16:45:11 GMT
Server: Apache/2.2.3
Transfer-Encoding: chunked
Content-Type: text/html
Resources: RFC 2616