The Web, HTML, Malware, and Passwords (Week 12) Flashcards
What is the Internet?
Internet is a network of networks. It’s a loose, unstructured, ad hoc, chaotic collection of networks, all connected to each other.
Internet – first link was established in 1969
Internet ≠ World Wide Web
What is the World Wide Web (WWW)?
The Web are the pages viewed at a computer/mobile device. The web is a collection of information that can be accessed via the Internet.
The World Wide Web was invented in 1989 by Tim Berners-Lee at the European Org. for Nuclear Research (CERN)
What are the Building Blocks of the World Wide Web (WWW)?
Berners-Lee created the building blocks of the WWW
* URL system – Uniform Resource Locator
* HTTP – Hypertext Transfer Protocol
* HTML – Hypertext Markup Language
* First text-based browser (in 1990)
What is Uniform Resource Locator (URL)?
What are the parts of an URL?
e.g. http://camosun.ca:80/about/documents/la_map.pdf
- Method of describing locations of resources (files, documents, etc.)
- e.g.: http://camosun.ca:80/about/documents/la_map.pdf
http = protocol
://camosun.ca = Host Name
:80 = Port
/about/documents/ = path
la_map.pdf = File Name
What does the Hypertext in Hypertext Transfer Protocol (HTTP) mean?
Text that contains hyperlinks, which are references to other documents that we can follow by clicking – commonly called links.
(See 10.1 How the Web Works in the text)
What is Hypertext Markup Language (HTML)?
HTML is the code that is used to structure a web page and its content.
Think of this as the layout of content. A layout is a structure (the skeleton) of a page. It could include set of paragraphs, a list of bulleted points, or using images and data tables.
What are 5 major properties of Hypertext Markup Language (HTML)?
- Hypertext Markup Language (HTML): HTML is the standard markup language used to create and structure content on the World Wide Web.
- HTML provides a set of elements or tags that define the different parts of a web page, such as headings, paragraphs, links, and images.
- Semantics: HTML is designed with a focus on semantic meaning. Each HTML tag carries a specific meaning, indicating the purpose or role of the content it encloses. This semantic structure helps search engines, browsers, and other devices to interpret and present web content appropriately.
- Cross-Browser Compatibility: HTML is a key component of web standards, promoting consistency and interoperability across different web browsers. By adhering to HTML standards, developers can create web pages that display consistently and correctly across various browsers and devices, providing a seamless user experience.
- Document Structure: HTML defines the overall structure of a web document. It consists of a hierarchy of elements, starting with the
<html>
tag, which contains the entire document, and includes essential sections like<head>
for metadata and<body>
for the main content. This hierarchical structure organizes content and ensures proper rendering by web browsers.
What are 5 major properties of Hypertext Markup Language (HTML)?
(Shorter Version)
- HTML is the standard markup language used to create and structure content on the World Wide Web.
- HTML provides a set of elements or tags that define the different parts of a web page
- Semantics: HTML is designed with a focus on semantic meaning. Each HTML tag carries a specific meaning, indicating the purpose or role of the content it encloses.
- Cross-Browser Compatibility: HTML is a key component of web standards, promoting consistency and interoperability across different web browsers.
- Document Structure: HTML defines the overall structure of a web document. It consists of a hierarchy of elements.
What are Cascading Stylesheets (CSS)?
Cascading Stylesheets enable us to separate document content and its presentation
Allows for more flexibility in web page design and styling.
Allows for design efficiency and accuracy.
Originally, HTML came without CSS => content and presentation information were closely intertwined – e.g. inline styling.
CSS helps to present content of the same HTML document on devices with different screen sizes
(Lab 08 HTML/CSS)
What is a Client-Side Scripting?
Client-side scripts (like JavaScript programs) run locally in a browser and enable interactivity (behavior
of the page) on top of HTML and CSS
When you visit a website, your web browser downloads the web page, and if the page contains client-side scripts written in languages like JavaScript, those scripts are executed on your computer.
This allows dynamic changes on the page without having to communicate with the server again. Common tasks handled by client-side scripting include form validation, animations, and interactive features
What is Server-Side Scripting?
Many web sites also use server-side scripts that are executed by the web server and process user input
Server-side scripting involves scripts or code that run on the web server, processing requests and generating dynamic content before sending it to the user’s browser.
When you interact with a website by submitting a form, requesting information, or logging in, the server-side scripts operate.
These scripts are responsible for handling data, interacting with databases, and performing tasks that require server resources.
Once the server processes the request, it sends back the relevant information to the user’s browser, which can then be displayed or used to update the web page. Common server- side scripting languages include PHP and Python.
What is Active Content in Web pages and Browser Extensions?
Active content in web pages
* Web browsers also support the use of executable code (active content) besides JavaScript, e.g. Apple QuickTime and Adobe Flash (although less popular now)
Browser extensions (plug-ins)
* Enable features of hardware or software that is usually not accessible with HTML, e.g. file access on local machine, specialized camera access, etc.
Caution: we are at the mercy of downloaded executable code and often do not have control of the code performed on our computers. Be careful what you download and install!
What is HTTP?
Hypertext Transfer Protocol is the foundation of data communication on the World Wide Web.
It is an application layer protocol that facilitates the exchange of information between a web server and a client, typically a web browser.
HTTP is the protocol that enables the retrieval and display of web pages, linking together various resources on the internet.
What does it mean to “Maintain State” in HTTP sessions?
HTTP is “stateless” => a server is not required to keep information between subsequent requests of the same client (called a “session”)
* meaning each request and response are independent of previous ones. The server does not retain information about the client’s previous requests. To maintain a form of state, technologies like cookies and sessions are often used.
* This is an obstacle for any site that wants to authenticate users with a login
Advantages/disadvantages of keeping state information in a session
* Allow browsing inside a password protected space
* Allow “personalized” looks and preferences
* Allow shopping cart transactions
* Allow focused advertising
* Allow tracking of web usage
What is a HTTP Cookie?
One solution to maintain the state of a session are cookies
* A cookie is a small text file (max 4000 bytes)
* Cookies are sent to the browser together with the requested web page
* They are tied to a specific domain name and saved in local storage by the browser until their expiry date
* On the next interaction (with a server of the same domain), stored cookies are sent over to the server automatically with any HTTP request
Most browsers offer “private” or “incognito” browsing: cookies are only kept for the duration of the current browsing session