WWL/HTML Flashcards
Who invented WWW
Tim Berner Lee
What is WW?
- A way of accessing the information on the Internet
What is information encapsulated and viewed in?
- Information is encapsulated in a web page and viewed in web browser (e.g google chrome)
Client-Server Model
- Describes the interaction of networked computers
- Clients request information from servers
- Servers respond with the information (if applicable)
What is the web server?
- A computer set up to respond to requests for web pages
Server Codes
Web Server; HTTP
File Server: FTP
Mail Server: SMTP
HTTP (Hyper Text Transfer Protocol)
- Method of requesting and transmitting web pages
How does communication between client computers and web servers happen?
- Done by sending HTTP Requests and receiving HTTP Responses
What happens when a clicks on a link or enters a URL in a browser?
- A request is sent to the HTTP port (80 or 8080) of the associated web server
What are web analytics?
- Collection and analysis of data regarding website usage
Why are web analytics used?
- Used by website owners to track the number and
behavior of users visiting their sites
What is HTML? (HyperText Markup Language)
- Defines content of web page as text file with .html extension
Escape Characters
- Characters that are used in HTML in addition to
ordinary text and need to be represented
by a character sequence
Special Characters
- A character that is not an alphabetic or numeric character.
- Entered in unicode using hex/dec notation
What are the three components of a webpage?
-HTML (Content and Strucutre, CSS (Presentation), Javascript (behaviour)
Forms
- Allow users to provide information that is sent to a server for storage (e.g., creating a new account) and processing (e.g., making an online purchase)
What are the three ways CSS can be added to HTML elements?
- Inline - by using the style attribute in HTML elements
- Internal - by using a element in the section
- External - by using an external CSS file
Inline CSS
- An inline CSS is used to apply a unique style to a single HTML element.
Internal CSS
- An internal CSS is used to define a style for a single HTML page.
What can Java Script Change?
- Browser characteristics (e.g., display size, orientation, device)
- User actions (e.g., mouse movement, clicks, scrolling)
What are Cookies used for?
- Cookies are used to store permanent ID about a client’s visit to a specific web server such as:
- Identification information (e.g., username and credentials)
• Display preferences (e.g., preferred shopping categories)
• Shopping information (e.g., items browsed, items in your cart)
• Regional and language preference
Tracking Mechanisms:
- Cookies
- Browser Fingerprinting
- browser version, language preference, installed fonts, plug-ins, … may (uniquely) identify you without the use of cookies - Javascript
- Web Beacon/Web bug
Security Risks- Clients
- Phishing
- Malware
- Trojan
- Vrius
- Worm
Types of Malicious Software
- Virus
- Worm
- Trojan
Trojan
- Invade your computer disguised as a real, operational program.
Types of Malicious Actions by Trojan
- RAT (Remote Administration Tool): can activate and
broadcast images from a webcam - Key logger: capture and transfer typed data (passwords)
- Backdoor: Provide remote access and control
- Ransomware: encrypt user data to extort money from owner
Virus
- Can corrupt, delete, or steal data; can disrupt computer system
- Spreads by “infecting” (attaching itself to) other files that are shared between computers
Worm
- Does not attach itself to a file to spread
- Able to replicate itself autonomously over networks
Security Risks-Server
- An attack meant to shut down a machine or network, making it inaccessible to its intended users
Distributed Denial of Service Attack
- DoS attack from hundreds, thousands, or millions of clients from many different computers
Security Risks-Communication
- Man-in the middle
- Typically uses lure of “free Wi-Fi” in coffee shops, airports, etc.
Security Risks-Communication Migitation Measures
- Use HTTPs connections when avaiable
- Use a virtual private network (VPN) service
