Web Technologies questions
Explain the automated process that takes places that allows customers to access the site when they enter the domain name into their browser
(Customers enter) domain name and this is sent to DNS servers. DNS servers map this domain to an IP address If the DNS server can't resolve, it passes the request (recursively) to another DNS server. DNS Server sends the IP address to browser... ... so it can retrieve the website from server on which it is hosted.
Give one disadvantage of this code being run client side rather than server side.
- Won't work if JavaScript is disabled. (1) - Shows incorrect message if user's computer's clock is wrong/in different time zone. (1) - (Source) code is visible allowing it to be copied/modified. (1)
Explain what happens when a search engine indexes the page. You do not need to discuss ranking
A program called a spider/crawler/bot - Traverses the web / following the links. - It takes each word in the document - ...It adds an entry for the page (under the word) in the index... - ...alongside the word's position on the page.
Many websites try to ensure they are accessible to all visitors regardless of disability, language spoken or the device being used to access it. Discuss the technical and design measures that can be taken to ensure a website is accessible.
AO1: Knowledge and Understanding Methods of improving accessibility: - Using text alternatives for images - Changing styles using CSS - Avoiding combining colours that may be indistinguishable by those with colour blindness. - Using character sets and fonts that support different alphabets. -Using server side processing to amend the content shown. - Writing web pages to facilitate screen readers (such as giving hyperlinks meaningful names and not just "click here"). - Using tables for tabular data (as they are intended) and not layout (again to aid screen readers). - Ensuring that all content can be accessed with the keyboard alone in a logical way. - Avoiding CAPTCHA.
Given that computers store everything in binary, explain how they are able to represent text
Computers use a character set/ASCII/ UNICODE - To map binary values to characters - Each character is represented by a unique value
Several of these photo frames can be placed around a house and connected in a peer to peer network. Describe what is meant by the term 'peer to peer network'.
Devices on the network have equal status/no (central) server. - Devices on the network share data
Explain the difference between a HTML id attribute and a HTML class attribute.
Only one element can have a given id/id is unique. (1) Class can be used assigned to multiple elements/used multiple times. (1)
The photo frames can also play video clips. Due to the limited storage on the device the videos are stored on the company's servers (i.e. 'in the cloud') and streamed when needed. Give one disadvantage to the user of using cloud storage for their photos.
Potentially vulnerable to hacking. - Reliant on an internet connection/requires a fast enough internet connection. - Reliant on company servers.