What are pseudo elements

Pseudo-elements are a special selector in CSS that are used to insert content at specific locations on an element. They are called "pseudo-elements" because they are not elements that actually exist in the HTML document. Instead, it is created through CSS. It can be used to insert content before or after an element, or at a specific location inside an element, usually to add a decorative effect or change the appearance of an element. In CSS, pseudo-elements are represented by double colons instead of single colon. This is to distinguish them from pseudo-classes, which are represented by single colon.

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

Pseudo element is a special selector in CSS that is used to insert content at a specific location on an element. They are called "pseudo-elements" because they are not elements that actually exist in the HTML document, but are created through CSS.

Pseudo elements can be used to insert content before or after an element, or to insert content at a specific location inside an element. They are often used to add a decorative effect or change the appearance of an element.

In CSS, pseudo-elements are represented by double colons (::) instead of single colons (:). This is to distinguish it from pseudo-classes, which are represented by a single colon.

Common pseudo-elements include the following:

1. ::before: Insert content in front of the element. You can use the content attribute to define the content to be inserted.

2. ::after: Insert content after the element. You can also use the content attribute to define the content to be inserted.

3. ::first-line: Selects the first line of the element and can apply styles to it.

4. ::first-letter: Selects the first letter of the element and can apply styles to it.

5. ::selection: Selects text selected by the user and can apply styles to it.

Using pseudo elements can achieve some interesting effects. For example, you can use the ::before pseudo-element to add icons or decorative symbols without adding additional elements to the HTML. You can also use the ::after pseudo-element to add some extra content, such as reference tags or comments.

Pseudo elements can also be used with CSS animations and transitions to create more complex effects. By applying animation or transition to pseudo elements, dynamic effects such as gradient, rotation, and scaling of elements can be achieved.

It should be noted that pseudo-elements can only be used on block-level elements, not on inline elements. In addition, the content of pseudo elements is generated through CSS and does not appear in the DOM, so it cannot be manipulated through JavaScript.

In summary, a pseudo element is a special selector in CSS that is used to insert content at a specific location on an element. They can be used to add decorative effects or change the appearance of elements, and are a powerful tool for achieving some interesting effects.

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