What is the abbreviation for Division : block is a tag that holds many other tags inside and divides the HTML document into different parts. So the div tag is also used to present the layout of the web page.

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CSS (Cascading Style Sheets ): is the code you use to style your web pageHow to use CSS:Inline CSS: apply to an HTML element.Internal CSS: apply to an HTML page External CSS: apply to an HTML element Multi-page HTMLWith External CSS you can change the look and feel of an entire web page by changing a single file.Example: Inline CSS

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Common CSS Selections

Selection based on tag name

For example: Format the h1 tag, the selection will be h1 as follows:

This is a simple format, but it is not recommended to use much because of course, when you format it like this, all the h1 tags in the web page will turn into this format. For example, in a website with 100 h1 tags, all of those 100 tags have the same color as above.

Selection based on id

When it comes to id, it means unique without duplicates. If you intentionally give multiple id names the same, the code will still run normally, but when it comes to server-side programming, it will fail. So don’t use the same id names. Using id you will be able to format the tags as you like.

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For example: Format h1 tag based on id=”nenvang” then the code of h1 tag will be as follows:

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Lesson 1:

Lesson 2:


Lesson 3:

Lesson 3.1:

Lesson 4:

Lesson 5:




Lesson 6:


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Link to download Reference Exercises:

De exam : https://drive.google.com/file/d/17eQrQVQWiDJVN87__UOMdRDpGnZaLaTp/view?usp=sharing