Subtopic Notes
5.1 The internet and the world wide web
5. The internet and its uses
| The Internet | World Wide Web (WWW) |
|---|---|
| Underlying infrastructure connecting computers and networks globally | Collection of websites and web pages accessed using the internet. |
| Uses TCP1/IP Protocol | Uses HTTP/S protocol. Pages written in HTML |
| Stands for interconnected network | Stands for World Wide Web |
| URL specify the location of web page |
Uniform Resource Locator (URL)
- Text-based address for a web page (Userfriendly version of the IP Address)
Hypertext Transfer Protocol Secure (HTTPS)
- The protocol for exchanging or transferring hypertext safely
- Specifies how messages are formatted and transmitted and the actions that web servers and browsers should perform in response to different commands
- Foundation for data communication on the World Wide Web
Web Browser
- Purpose
- Function
- Storing bookmarks and favorites
- Recording user history
- Allowing use of multiple tabs
- Storing cookies
- Providing navigation tools
- Providing an address bar
Process of loading web pages
- User writes or visits the URL in the browser
- Browser checks its cache if the domain was accessed recently
- If not found in cache, the browser sends the URL to the domain name server (DNS)
- DNS matches it with the corresponding IP
- If the IP exists, it is sent to the browser, else error shown
- Browser sends a http request to the IP of the web server
- Web server processes it by looking for the requested files
- Web server sends an HTTP response back along with status code
- Browser interprets the HTML downloading any other resources linked like CSS, JavaScript or Images
Cookies
- Small text files stored on the user’s computer when a website is visited
- The files are detected by the website when it is visited again
- Functions
- Saving personal details
- Tracking user preferences
- Holding items in an online shopping cart
- Storing login details
- Store internet surfing habits
- Carry out targeted advertisements
- Store payment details
- Store progress in online games or tests
| Persistent Cookies | Session Cookies |
|---|---|
| Stored on the hard disk until their expiration date or until the user removes them. | Temporary cookies that are stored in RAM till browser is closed Example: Shopping Cart |
| Might keep information on the user | Doesn’t collect information on the user |
| May pose privacy concerns | More secured |