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This article mainly shows you the "css3 attribute double colons what is the use", the content is easy to understand, clear, hope to help you solve the doubt, the following let the editor lead you to study and learn "what is the use of css3 attribute double colons" this article.

The double colon of the css3 attribute indicates that the attribute is a pseudo-element selector, a selector for creating and styling elements that are not in the DOM tree. Css3 pseudo elements include ":: after", ":: before", ":: first-letter", ":: first-line", and so on.

The operating environment of this tutorial: windows7 system, CSS3&&HTML5 version, Dell G3 computer.

The double colon of the css3 attribute indicates that the attribute is a pseudo-element selector.

What are pseudo elements?

Pseudo-element literally means "false element" or "camouflage element". In fact, it can also be understood that pseudo elements are actually virtual elements, elements that do not exist (code form), you do not find them in the document, so pseudo elements are virtual elements.

Pseudo elements are selectors for creating elements that are not in the DOM tree and adding styles to them.

With pseudo elements, you can define styles for specific parts of the selected element without the help of the ID or class attributes of the element. For example, with pseudo elements, you can style the first letter in a paragraph, or insert something before or after the element, and so on.

A series of pseudo elements are provided in CSS, as shown in the following table:

Pseudo-element example description:: afterp::after in each

Insert content after the element:: beforep::before in each

Element:: first-letterp::first-letter matches each

The first letter of the content in the element:: first-linep::first-line matches each

The first line of the element:: selectionp::selection matches the element selected by the user:: placeholderinput::placeholder matches the placeholder attribute of each form input box (for example). Above is all the content of the article "what is the use of double colons with css3 attributes?" Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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