- When you type in a URL / click on a link the browser sends the URL to the DNS using HTTP
- The DNS finds the matching IP addresses for the URL and sends the IP address to the web browser
- The web browser sends a request to the web server for web pages
- The web pages are sent from the web server to the browser
- The browser renders HTML to display web pages
- Any security certificates are exchanged
- SSL/HTTPS is used to secure the data which will encrypt any data that is sent
Structure & Presentation
Websites can be separated into structure and presentation.
HTML is:
- A language used to create the structure/layout of a website
- Written in plain text
- Used in the content layer
- Made up of a set of markup codes
- Used to tell the browser how to display the page
E.g.
- Where text is placed
- Margins of page
- Line break
- Padding
CSS is:
- A language used to create the presentation / formatting of the page
- Written in plain text
- Used in the presentation layer
- Used by web pages to produce a consistent format between different web pages
E.g.
- Font size
- Font colour
- Background colour
Why are they kept separately?
- The presentation of the page can be changed without needing to alter the structure so regular updates can be made without needing to check the structure
- The formatting document (written in CSS) can be used again for a different website
- If further content and web pages are added to the website, the necessary formatting can be easily applied so this can save time when developing a website
- CSS to standardise formatting so CSS only needs to be created once and be applied to each webpage
- One person can develop the structure and one can develop the presentation so this can save time when developing and updating a website
