Web Applications

Internet is a global communication linking geographically seperated locations together through telephone lines and satelite.

Any device can be linked to the internet because of common technological standards (protocols)

URL Uniquely identifies webpages on the internet.

http://CCEA.org.uk/DigitalTechnology.html

http:// -  Protocol for accesing the resources

.org - Top level domain

.uk - Domain name - Name of the site

/DigitTechnology.html - Filename of any extension

Protocol for identifying, requesting and transfering multimedia webpages over the internet.

Created using HTML

http(s) - Secure

The IP Address is the physical address linking a computer to the internet.

Some devices are connected constantly with a dynamic IP Address. Other devices connect through an ISP which are assigned a dynamic IP Address.

The DNS connects a domain name to an IP Address.

158.152.1.58 ---> DNS ---> http://www.google.co.uk

"A web browser is the application running on a user's computer that is responsible for requesting the text and graphics of  a webpage from servers on the internet, and assembling them for display"

• Chrome
• Firefox
• Opera
• Safari

Web browsers usually have functionality like Favourites and History.

A web server provides internet pages for other computers throug the internet. It often provides the cache of webpages, which are pages stored when first accesed so they can be supplied later without the delay of the internet.

Web hosting enables users to upload their webpage so that it is accessible over the world wide web. The space is usually rented out and is hosted from a data center.

FTP is the common method of transferring files over the internet. The user requests a file from the server that is hosting it and they can grant the request.

Websites are often uploaded over FTP.

The internet service provider is an organisation that controls the transmitions to the internet from the users.

Commericial service providers are;

• Sky
• BT
• EE
• TalkTalk

A search engine accesses the world wide web that indexes web pages, Users can search a keyphrase or term into a search engine and it will return a hyperlink that is relevant,

A search engine can index millions of webpages making search engines important for commercial websites.

The cache is the store of the most recently used resources, (Webpages, images). The cache is located near the CPU making extremely fast R/W speeds, faster than RAM. If a user revisits a webpage it can load extremely fast.

Some websites reuse certain assets such as a logo, this logo can be stored in the cache and will not need to be redownloaded everytime, saving time and data.

If a user reloads a website to see new content and a cached version is shown it will not be up to date.

Cookies are small files placed on the hard drive of a user's computer by a website that they've visited. When they return to the website the website will notice the cookies on the computer and will know they've visited before.

The owner of the site is able to build up a profile of what the user sees on repeated visits.

A portal is a wbsite deisgned to be the one that a user will want to visit first when accessing the web. There are obvious commercial advantages for a portal in attracting as many users as possible, because they can sell advertising on the site. To be useful to the individual, the site must offer services that the user needs regularity, such as search facilites, news updates and so on.

A website is a collection of webpages hyperlinked together under the same domain name. They often have a common theme across all webpages.

A webpage is a document accesed in a browser. It often contains text, images, audio and video. The web browser reads the document and is able to interpret the data so that it can be presented for the reader.

Each webpage has a unique URL.

The world wide web is a collection of information that has grown up on a computer connected to the internet. This information is held in multimedia form and is stored in locations called websites in the form of webpages.

Searching through the WWW is described as 'Surfing'.