How many types of pseudo elements are there?

There are five pseudo-elements, namely::before, ::after, ::first-letter, ::first-line and ::selection. Detailed introduction: 1. ::before, insert a pseudo element before the content of the selected element. It can be used to add some style effects in front of the element, such as adding icons, reference symbols, etc. When using the pseudo element::before, you need Set the content attribute to specify the content to be inserted; 2.::after and so on.

The operating system for this tutorial: Windows 10 system, DELL G3 computer.

Pseudo-element is a special selector in CSS used to add additional style and content to selected elements. They are used to create elements that do not exist in the document to achieve more styling effects and layout control. In CSS, pseudo-elements are represented by double colons (::).

Currently, there are five pseudo-elements in CSS, which are:

1. ::before: Insert a pseudo-element before the content of the selected element. It can be used to add some style effects in front of elements, such as adding icons, reference symbols, etc. When using the pseudo element::before, you need to set the content attribute to specify the content to be inserted.

2. ::after: Inserts a pseudo element after the content of the selected element. Similar to ::before, it can also be used to add some style effects behind elements. The content attribute also needs to be set.

3. ::first-letter: Select the first letter or Chinese character of the selected element. By setting styles, you can change the size, color, font and other attributes of the initial letter. This pseudo-element can only be applied to block-level elements.

4. ::first-line: Select the first line of the selected element. By setting the style, you can change the size, color, font and other attributes of the first row. This pseudo-element can also only be applied to block-level elements.

5. ::selection: Select the part of the selected element that is selected by the user. By setting styles, you can change the background color, font color and other attributes of the selected text. This pseudo-element can be applied to any element.

These five pseudo-elements select elements through CSS selectors and insert pseudo-elements at specified positions of the selected elements. Their use can provide web designers with more style control and layout options, making web design more flexible and diverse.

It should be noted that pseudo elements can only be controlled through CSS styles and cannot be operated through JavaScript or other programming languages. In addition, different browsers have different levels of support for pseudo-elements, so you need to pay attention to compatibility issues when using pseudo-elements.

To summarize, a pseudo-element is a special selector in CSS that is used to add additional style and content to selected elements. There are currently five pseudo-elements, namely ::before, ::after, ::first-letter, ::first-line and ::selection. They can provide web designers with more style control and layout options, making web design more flexible and diverse.

The above is the detailed content of How many types of pseudo elements are there?. For more information, please follow other related articles on the PHP Chinese website!