Web Technologies Flashcards
What is HTML
A programming language used to define and interpret the content of web pages
What is CSS (Cascading style sheets)
- A programming language used to specify the layout and appearance of web pages
- It uses selectors such as classes and IDs
What is JavaScript
A programming language that programs the behaviour of web pages
What are the Two Sections of HTML
- The head - contains the title of the webpage
- The body - contains the content of the webpage
Describe the main HTML Tags
- < html > - All code written within these tags is interpreted as HTML
- < body > - Defines the the main content area of the webpage
- < link > - Used to link to additional files, including CSS stylesheets
- < head > - Defines the browser tab or window heading area
- < h1 >, < h2 >, < h3 > - Heading styles in decreasing sizes
How do you Show the End of a HTML Tag
< /html >
Describe Ordered and Unordered Lists in HTML
- Ordered - < ol > followed by < li >
- Unordered - < ul > followed by < li >
Describe the Extra HTML Tags
- < p > - a paragraph separated with a line space above and below
- < img > - self closing image with parameters (img src = location, height=x, width = y)
- < a > - anchor tag defining a hyperlink
- < div > - creates a division of a page into separate areas each which can be referred to uniquely by name, (< div id= “page” >)
Write the HTML code for a hyperlink
< a href = “booking.htm” > < img src = “ticket.pgn” > < / a>
What are the names of the two methods of applying CSS
- Internal/Embedded CSS - placed inside the style tags and is entered directly into the HTML document
- External CSS - written in a separate document and a link to this style sheet is added to the HTML document
How do you use External CSS in your HTML code
Write within the tag
Describe an Example of CSS Syntax
head{
background-color: #8EJH32
}
body {
background-color: white;
font-family: Arial,
font-size: 20px;
Text-align: center;
}
Is JavaScript interpreted or complied
- JavaScript is interpreted
- This means web pages are interpreted by the browser each time they are loaded
What are the Advantages of using JavaScript
- Javascript is interpreted so is often used to validate input data on the client computer
- Local computer can deal with invalid data before it is sent off to the servers
- Reduces web traffic
What is a Search Engine
A program that searches through a database of internet addresses looking for resources based on criteria set by the client
How does a Search Engine work
- Search engines use a software called web crawlers
- Web crawlers are used by search engines to collect information, it works by traversing the internet webpage by webpage looking for linked sites
- The web crawlers collect keywords and phrases from the linked web pages and add this information to the index
- They also collect and add meta data from websites, which is the information specified by the website owner
Why is it important the order in which Search Engines display webpages
- The order determines which websites users choose to visit and use
- Therefore it is important that search engines display the most high-quality websites with relevant content at the top of the page
What is the PageRank Algorithm
The algorithm that determines the order in which web pages are displayed when a search is conducted
The algorithm of pagerank itself is given by:
PageRank(x) = (1-d) + d[(PageRank(T1) ÷ Count(T1)) + … + (PageRank(Tn) ÷ Count(Tn)]
PageRank(x) is the page rank of page x, Count(Tn) is the total count of outbound links from a webpage n and d is the damping factor.
Why and how was the PageRank Algoirthm improved
- People tend to follow 5 or 6 links before breaking a chain, so we can improve Page Rank to account for this
- Damping represents the probability the user does click link
- We assume that the damping probability is 0.85
Describe the steps of the PageRank Algorithm
- Counts how many links leave each website
- Gives every website a page rank of 1
- Iterates a “vote” to improve its estimate until it converges
What factors determine a PageRank
- How many incoming links it has from other web pages
- The page rank of the web pages that link to it
Aside from links between websites what other factors affect the PageRank of a website
- The age of a web page
- How quickly content on the web page loads
- How often web pages are updated
What data structure is used to display a PageRank Algorithm
A Directed Graph
What is Server Side Processing
- Server Side Processing is when a client sends information to a server for processing
- This means no information is processed on the client computer
- Common server side scripting languages are SQL or PHP
What is Client Side Processing
- Client Side Processing is when information is processed on a local device
- This means all of the information is processed on the client computer
- Client Side Processing uses languages such as JavaScript
What are the Advantages of Server Side Processing and Client Side Processing
Server Side Processing -
- Does not require plugins
- Can perform large calculations much faster than clients
- Not browser dependent
- More secure
Client Side Processing -
- Webpage can immediately respond to user actions
- Executes quickly
