Tags for this article: basics, html, protocols, tutorial
Protocols are set of rules which define how the two computers will communicate with each other. Technically speaking, protocols define the procedures and standards which form the basis of transferring the data between two computers. In HTML protocols are used in order to tell the web servers and clients how to upload and download the data between each other via internet. Different types of protocols are used in HTML depending upon the type of file and its usage. The most common protocol used in HTML is HTTP which is short for Hyper Text Transfer Protocol. HTTP represents the basic information about the contents of the HTML documents according to their file name extensions. For eg. A file with .gif extension tells the web browser that its an image file and the browser processes that file as an image.
HTTP browsers don’t maintain a session with the web servers permanently. They retrieve a particular document from the web server via HTTP and then get disconnected. This means that while you view a web page, your web browser is not connected to the web server. When you enter a new URL or click on a link on the existing web page, the browser again connects itself with the web server, downloads the information and disconnect the session again.
HTTP was basically developed for handling hyper text pages over the internet. When HTTP is used, a series of operations is initiated to retrieve the information form the web server. Initially, when you type a URL in the address bar and hit Enter/Go button, the HTTP client (the web browser) makes a request to the web browser via internet connection. This establishes a Transmission Control Protocol (TCP) connection to a particular host on port 80 (because by default http service runs on port 80). The HTTP server listens to the client’s request on this port and provides the web page which is to be viewed.
HTTP uses TCP because a lot of data has to be transferred from the HTTP server to the client every now and then, and TCP gives surety of error free transmission of data. Besides HTTP there are other protocols also which are used over internet. Below is the list of protocols used for web browsers:
1) http:// It is used to retrieve HTML documents and associated files which
resides on the web.
2) file:// It is used to retrieve the documents which resides on the local
hard drive.
3) ftp:// It is used to upload and download the documents on an FTP
server.
4) gopher:// It is used to retrieve documents on a gopher server.
5) wais:// It is used to connect to a Wide area Information server (WAIS)
database.
6) mailto: It is used for sending e-mails to a specified address. It is not a
standard but it is supported by most of the web browsers today.
There is no need to put // with mailto:
7) news: Used to connect to a newsgroup or a specific article in the group.