HTTP (Hypertext Transfer Protocol)
Features:
- a client server connection is used where the browser is the client and the web server is the server
- there are 3 primary HTTP commands used in browsers: GET, HEAD and POST
- the GET command retrieves entire documents, this could be HTML files, images, video or other hypermedia files
- the browser requests a document from a certain web server by using a GET command and URL (Universal Resource Locator) of the document
- The web server responds to this request by transmitting the document to the browser
- The header of the document file indicates the nature of the data in the file. The browser reads the header data to determine how it should display the incoming data in the file
- the HEAD command retrieves just the header information of the file
- this command is used to check if the file has been updated since the browser last retrieved the file.
- if the file has not been update then the whole file is not retrieved instead the existing version is held in the browser is displayed
- the POST command is used to send data from the browser to the web server
- this command is used to send all data entered by users within web based forms (web based database)
Typical use:
- a primary protocol used by web browsers to communicate and retrieve pages from web servers