World Wide Web
Is the name given to the collection of informaton that has grown up on computers connected to the internet and which is made available for anyone to access.
Feautures of Pages on the World Wide Web:
- written using the programming language HTML
- viewed using a web browser
- contain HYPERTEXT which provides the user with clickable links to other pages on the web
- can contain sound, video, animation graphics and hypertext as well as simple text
- use Hyper Text Transfer Protocol to send pages across the internet.
It is a network of compters, each communicating with several other computers in the network, but not with all of them. It is a world-wide communications system linking computers in geographically seperate locations through the use of a variety of telecommunication links such as telephone lines and satellites.
Uniform Resource Locator
Is a reference to the address of a resource on the Internet.
Hypertext Transfer Protocol
An application protocol used on the world-wide-web.
It defines how data is structured and transmitted and specifies how browsers and web servers should act in response to requests.
Internet Protocol address
This represents a standard set of rules used to ensure the proper transfer of information between computers on the internet. They define how data is to be structured and what control signals are used.
Every device linked to a network using the TCP/IP protocol is identified by a unique IP address. The IP address allows messages and data to be routed to the correct address on the network.
IP addresses can be:
- Static - a permanent IP address that does not change.
- Dynamic - temporary addresses that are assigned each time a computer accesses the internet.
This software allows users to view and use web pages on the Internet. It is responsible for requesting the text and graphics of webpages from servers on the Internet, and assembling them for display.
These are usually in HTML format.
Web browsers can be used to view any HTML pages whether users are online or offline.
A computer designed to deliver Internet webpages across the Internet or within an Intranet. It processes requests for information that comes from the Internet infrastructure.
The web server contains application software to enable the transmission of content and makes use of client-server technology.
The program that accesses the application is called the client.
In order to have an Internet presence a web hosting service is required. This service provides individuals and organisations with access to a web server and web space to store a website or webpages.
The web host company will ensure that the website is available online and the service may include: web space to store the website, an e-mail feature, an interface for managin the website online, constumer support.
File Transfer Protocol
Is the most common protocol used to transfer files across the Internet between client and server devices.
Internet Service Provider
Has direct links to the internet and accepts transmission from users over communication lines and passes these onto the internet. The ISP sells internet access to companies or individuals and provides access to web servers which connect to the search engines on the internet.
An ISP will provide the user with a range of services:
- Variety of bandwidth options
- An email service
- Security features such as anti-virus, protection against hacking, viruses, spyware and identity theft
- Web hosting service which allows users to upload their own webpages
- Costumer support
- Website filtering which will filter out unsuitable content
- Telephone or Digital TV package
A search engine is a web-based tool that searches for information using keywords or criteria. The search engine will return results as website links based on the criteria provided. Some search engines use a spider or webcrawler. This programme 'crawls' through the web and constructs and index of pages. When a user wants to search for a topic using the Internet, the index of topics, made by the webcrawler is used. The webcrawler ensures that the index is up to date. Different search engines will search different servers to construct the index. This is why a search on Google may give a different result to a search of Firefox.
Meta tags can be used to specify key words in the heading of the HTML page. These words help search engines to categorise pages and decide whether or not to include them in the results for a particular search.
In the context of web application, cache or temporary internet files allow browsers to download website images, data and documents for faster viewing in the future. A local copy of the information is kept. This means that the browser will be able to load at least some information from each page you have visited without downloading that information again from the server. This can decrease the time it takes to load a webpage.
Small files downloaded to a computer when viewing a website. They can store previous activity on that site and user preferences. This information can be used when a user visits the site again. Cookies can be also used to track a users browser history over a period of time which can be considered a privacy concern. Users are generally asked to accpet the cookies associated with a website.
A website that acts as a main entry point to a group of web servies. Portals requre the user to log on and provide a range of servies such as: email, hyperlinks and search engines.
A website is a collection of HTML pages linked together on the world wide web.
A page of information stored on the world wide web.
Features of these pages are:
- written using HTML
- viewed using a web browser
- contain HYPERTEXT which provides the user with clickable links to other websites
- can contain sound, video, animation, graphics and hypertext as well as simple text