What are these two units about?
Part one of the Programming textbook has two units on the web: Web Applications (how they are built and how their parts talk) and Web Design and Media (how to make them easy and clear). This explanation is ours, to help you get the idea; the reference is the ministry's book.
What is a web application made of?
Every site you use, GoBachaloria included, has three parts:
- Frontend: what you see in the browser.
- Server, or backend: the part that thinks: who you are, and what you may see.
- Database: the part that remembers: your account, your lessons, your marks.
The frontend: three languages, three jobs
- HTML: structure. This is a heading, this is a button, this is an image.
- CSS: appearance. Colours, fonts and spacing.
- JavaScript: behaviour. You press a button and something happens.
An easy comparison is a house: HTML is the walls, CSS the paint and furniture, JavaScript the electricity.
What happens when you type a website address?
- The browser asks where that name lives (DNS).
- It sends a request to the server.
- The server prepares the page, perhaps asking the database.
- It sends back a response with a status code: 200 fine, 404 not found, 500 a problem on the server.
- The browser draws the page for you.
When the address is HTTPS, all of this is encrypted. Read about encryption in our cybersecurity explainer.
Web design and media
- Media: text, images, audio and video. Each has its formats, and the higher the quality, the bigger the file and the slower the page. The skill is in the balance.
- Information design: the most important thing first, clear headings, and not everything on one screen.
- User experience (UX): can people easily do what they came for? Are the buttons clear? When they press one, can they tell something happened?
- Evaluating websites: speed, ease of use, whether anyone can use it, and whether the content is accurate.
- Iterative improvement: build it, test it with real people, fix it, repeat.
A practice question (ours)
You open a site and get "404". Where is the problem? Answer: the page you asked for does not exist on the server, so the address is wrong or the page was removed. The server itself is working.
Learn it from someone who does it
Eng. Ahmed Tarek has built and run web platforms for years, and teaches these two units on the subject page. His first five videos are free.