Friday, October 29, 2010

WWW Browsers


To be used as a web client computer needs to be loaded with a special software tools, which is known as WWW browser (or browser in short). Browsers normally provide the following navigation facilities to help users save time when they are jumping from server to server while Internet surfing (the process of navigating the Internet to search for useful information:
1. Unlike FTP and Telnet, browsers do not require a user to remotely log in to a ser ver computer, and then to log out again when the user has finished accessing information stored on the server computer.
2. Browsers allow a user to specify and URL address for a server computer to facilitate the user to directly visit the server computer’s site, and to access information stored on it.URL stands for Uniform Resource Locator. It Is an addressing scheme used by WWW browsers to locate site on the Internet.
3. Browsers allow a user to create and maintain a personal hotlist of favorite URL addresses of server computers, which the user is likely to frequently visit in future. A user’s hotlist is stored on his/her local web client computer. Browsers provide hotlist commands to allow the user to add, delete, and update URL addresses in the hotlist, and to select and URL address of a server computer from the hotlist, when the user wants to visit that server computer.
4. Many browsers have a “history” feature. These browsers maintain a history of the server computers visited in a surfing session. That is, they save (cache) in the local computer’s memory. the URL addresses of the server computers visited during a surfing session, so that if the user wants to go back to an already visited server later on (in the same surfing session)
, the link is still available in the local computer’s memory.
5. Browsers allow a user to download (copy from a server computer to the local computer’s hard disk) information in various formats (i.e. as a text file, as an HTML file ,or as a PostScript file). The downloaded information can be later (not necessarily in the same surfing session), used by the user.
For Example, downloaded information saved as a Post Script file can be later printed on a Post Script. Compatible Printer, where even graphics will be properly reproduced.

Thursday, October 28, 2010

World Wide Web-WWW

The World Wide Web(Called WWW or W3) is the most popular and promising method of accessing the Internet. The main reason for its popularity is the use of a concept called hypertext. Hypertext is a new way of information storage and retrieval, which enables authors to structure information in novel ways. An effectively designed hypertext documents can help users rapidly locate the desired type of information from the vast amount of information on the Internet. Hypertext documents enable this by using a series of Links. Link can be shown on the screen in multiple ways, such as a labeled button, highlighted text, or different color text than normal text if your computer has a color display, or author-defined graphic symbols. A link is a special type of item in a hypertext document, which connects the document to another document that provides more information about the linked item. The latter document can be anywhere on the Internet (in the same document in which the linked item is, in the same computer in which the former document is, or in another computer, which is at the other end of the world).By “connect” we mean that a user simply selects the linked item (using a mouse or key command) and the user almost immediately sees the other document on his/her computer terminal.

The concept of hypertext can be best illustrated with the help of an example. Let us assume that the screen of your computer terminal has the following hypertext document currently displayed on it:

Naveen Kumar Kumawat is the writer of this blog which provides information about the Computer Science and Internet Bazaar. At Present Kumawat is working at the OffSite Network Operation Center(OffSiteNOC),Jaipur

This hypertext document has the following two links,which are shown on the screen as highlighted (bold and underlined) texts:
1. Computer Science .Let us assume that this link connects the current document to another document, which gives detailed information about Computer Science.
2. OffSite Network Operation Center (OffSiteNOC).Let us assume that this link connects the current document to another document, which gives detailed information about OffSiteNOC and located on jaipur.

Now, if you use your mouse to click anywhere on the link Mail Bazaar of the displayed document, within a few seconds you will find yourself connected to the computer at Computer Science and displayed on your computer screen will be the documents, which gives detailed information about OffSiteNOC of Jaipur.Hypertext documents on the Internet are known as Web Pages. Web Pages are created by using a special language called Hyper Text Markup Language (HTML in Short) .HTML is a subset of the more generalized language called Standard Generalized Markup Language (SGML In short), which is a