Karteikarten
Ohne Titel
Karten in diesem Stapel (22)
- 1This course uses a web-centric approach to introduce a # of topics related to• data organization
• markup languages
• procedural programming
• event handling
• and the web - 2this course will give you a taste of .. (and are the basic building blocks of the world wide web)• HTML & CSS
• JavaScript
• Web forms
• Client-Server Concepts - 3HTML (and CSS) is not a programming language, It isa “markup language” that has many rules that are similar to programming languages
- 4JavaScript is a scripting language and is• JS is a full programming language
• It can be used to dynamically update a webpage
• Direct interaction with a webpage using the "Document Object Model" (DOM)
• Can be used to access web servers to retrieve data
• JavaScript is an event-driven language that responds to actions applied in an HTML page
• In is among the popular languages are used in the tech industry (9th most in-demand) - 5Anytime you visit a website (Ex. youtube) you are . .in a client server setting
- 6Html is for and CSS is for• Html is for CONTENT and STRUCTURE
• Css is for APPEARANCE - 7Programming isa multi-disciplinary domain, you need ALOT of practice
- 8What is the Internet? Is the World Wide Web (WWW) and the internet the same?• A collection of computer networks that use a protocol to exchange data
• No, The internet is a huge network of computers all connected together. The world wide web ('www' or 'web' for short) is a collection of webpages found on this network of computers. - 9Brief history• Began as a US Department of Defense network called ARPANET (1960s-70s)
• Packet switching (in the 60s)
• E-mail is born on 1971
• TCP/IP beginning on 1974 (Vinton Cerf) USENET (1979)
• By 1987: Internet includes
nearly 30,000 hosts - 10Brief history (cont.)• WWW created in 1989-91 by Tim Berners-Lee
• Popular web browsers released:
• Netscape 1994
• IE 1995
• Amazon.com opens in 1995 Google, January 1996
• Wikipedia launched in 2001 MySpace opens in 2003
• Facebook February 2004 - 11Key aspects of the Internet• Sub-networks are independent
• Computers can dynamically join and leave the
network
•Built on open standards
•Lack of centralized control (mostly)
•Everyone can use it with simple, commonly available software - 12People and organizations• Internet Engineering Task Force (IETF): internet protocol standards
• Internet Corporation for Assigned Names and Numbers (ICANN): decides top-level domain names
• World Wide Web Consortium (W3C): web standards - 13Layered architecture• The internet uses a layered hardware/software architecture (also called the "OSI model"): OSI model
• physical layer : devices such as ethernet, coaxial cables, fiber-optic lines, modems
• data link layer : basic hardware protocols (ethernet, wifi, DSL PPP)
• network / internet layer : basic software protocol (IP)
• transport layer : adds reliability to network layer (TCP,
UDP)
• application layer : implements specific communication for each kind of program (HTTP, POP3/IMAP, SSH, FTP) - 14Internet Protocol (IP)• Simple protocol for data exchange between computers
• IP Addresses:
- 32-bitforIPv5 -(Fournumbersbetween0-255)
- 128-bit for IPv6 - 15Transmission Control Protocol (TCP)• Adds multiplexing, guaranteed message delivery on
top of IP
• Multiplexing: multiple programs using the same IP address
• Port: a number given to each program or service
- port 80: web browser (port 443 for secure browsing)
- port 25: email
- port 22: ssh
• Some programs (games, streaming media programs) use simpler UDP protocol instead of TCP - 16Web servers and browsers• Web servers: software that listen for web page requests and returns web page content
• Web browsers: fetches/displays documents from web servers - 17Web Servers• Web server: software that listens for web page requests
- Apache
- Microsoft Internet Information Server (IIS) - 18Web Browser• Web browser: fetches/displays documents from web servers
- Mozilla Firefox
- Microsoft Internet Explorer (IE) Apple Safari
- Google Chrome
- Opera - 19Domain Name Server (DNS)• Set of servers that map written names to IP addresses
- Example: yorku.ca → 130.63.236.137
• Many systems maintain a local cache called a hosts file
- Windows: C:\Windows\system32\drivers\etc\hosts
- Mac: /private/etc/hosts
- Linux: /etc/hosts - 20Uniform Resource Locator (URL)• An identifier for the location of a document on the web
• URL lets your browser know what type of protocol
• What is the host (DNS server will find the IP)
• What webpage to get (path) - 21More advanced URLs• anchor: jumps to a given section of a web page: http://www.textpad.com/download/index.html#downloads
- fetches index.html then jumps down to part of the page labeled “downloads”
• port: for web servers on ports other than the default 80:
http://portquiz.net:8080/
(port 8080)
• query string: a set of parameters passed to a web program:
http://www.google.com/search?q=poutine
- parameter q is set to "poutine" - 22Hypertext Transport Protocol (HTTP)• Set of commands understood by a web server and sent from a browser
• Some HTTP commands (your browser sends these internally):
- GET filename : download
- POST filename : send a web for response
- PUT filename : upload
• Exercise: simulate a browser with a terminal window (see next slide)
Informationen
- Beschreibung
- Karteikarten am Ohne Titel, erstellt von sarru s am 21/10/2018.
- Erstellt von
- sarru s
- Aufrufe
- 0
- Bewertung