


What is the difference between pseudo-classes and pseudo-objects (pseudo-elements) in css
Pseudo classes are used to add special effects to certain selectors; pseudo elements are used to add special effects to certain selectors. The effects of pseudo classes can be achieved by adding actual classes; the effects of pseudo objects can be achieved by adding actual elements. Simply put, their essential difference creates new elements whether abstract or not.
The operating environment of this tutorial: Windows 7 system, CSS3 version, Dell G3 computer.
The fundamental difference between pseudo-classes and pseudo-elements (pseudo-objects) is whether they create new elements.
Pseudo element/pseudo object: It does not exist in the DOM document. It is a virtual element and creates a new element. Represents a child element of an element. Although this child element exists logically, it does not actually exist in the document tree.
Pseudo-object selector
Properties | CSS Version Version | Inherit From Parent Inheritance | Description Introduction |
---|---|---|---|
CSS3/CSS1 | None | CSS2/CSS1 E:first-letter/E::first-letter pseudo-object selector , sets the style of the first character within the object. | |
CSS3/CSS1 | None | CS3/CSS1 Pseudo The object selector E:first-line/E::first-line sets the style of the first line within the object. | |
CSS3/CSS2 | None | CSS3/CSS3 pseudo-object selector E :before/E::before, sets the content that occurs before the object (according to the logical structure of the object tree). Used with the content attribute | |
CSS3/CSS2 | None | CSS3 /CSS2 pseudo-object selector E:after/E::after, sets the content that occurs after the object (according to the logical structure of the object tree). Used with the content attribute | |
CSS3 | None | CSS3 pseudo-object selector E: :selection, sets the color of the object when it is selected. |
Properties | CSS Version Version | Inherit From Parent Inheritance | Description Introduction |
---|---|---|---|
CSS1 | None | CSS1 pseudo-class selector E:link, sets the style of hyperlink a before it is accessed. | |
CSS1 | None | CSS1 pseudo-class selector E:visited, set the hyperlink a in it The link address has been accessed in an outdated style. | |
CSS2 | None | CSS2/CSS1 pseudo-class selector E:hover, set the element in it Style on mouseover. | |
CSS2/CSS1 | None | CSS2/CSS1 pseudo-class selector E:active, set element Style when activated by the user (an event that occurs between mouse click and release). | |
CSS2/CSS1 | None | CSS2/CSS1 pseudo-class selector E:focus, set element Style when input focus occurs (the element's onfocus event occurs). | |
CSS2 | None | CSS2 pseudo-class selector E:lang() matches using special E element of language. | |
CSS3 | None | CSS3 pseudo-class selector E:not() matches does not contain The element E of the s selector. | |
CSS3 | None | CSS3 pseudo-class selector E:root, matches the E element in the document root element. | |
CSS2 | None | CSS2 pseudo-class selector E:first-child matches the parent element The first child element E. | |
CSS3 | None | CSS3 pseudo-class selector E:last-child matches the parent element The last child element E. | |
CSS3 | None | CSS3 For example, the selector E:only-child matches the parent element The only child element E. | |
CSS3 | None | CSS3 pseudo-class selector E:nth-child (n) Matches the nth child element E of the parent element. | |
CSS3 | None | CSS3 pseudo-class selector E:nth -last-child(n) matches the nth child element E from the bottom of the parent element. | |
CSS2 | None | CSS3 pseudo-class selector E:first-of- type matches the first sibling element E of the same type. | |
CSS3 | None | CSS3 pseudo-class selector E:last-of- type matches the last sibling element E of the same type. | |
CSS3 | None | CSS3 pseudo-class selector E:only-of- type, matches the only sibling element E of the same type. | |
CSS3 | None | CSS3 pseudo-class selector E:nth -of-type(n), matches the nth sibling element E of the same type. | |
CSS3 | None | CSS3 pseudo-class selector E :nth-last-of-type(n) matches the penultimate nth sibling element E of the same type. | |
CSS3 | None | CSS3 pseudo-class selector E:empty matches no child elements (including text node) element E. | |
CSS3 | None | CSS3 pseudo-class selector E:checked matches the selected state on the user interface The element E. (For form elements with input type of radio and checkbox) | |
CSS3 | None | CSS3 Pseudo The class selector E:enabled matches the element E in the enabled state on the user interface. | |
CSS3 | None | CSS3 pseudo-class selector E:disabled matches the disabled state on the user interface The element E. | |
CSS3 | None | CSS3 pseudo-class selector E:target matches the E element pointed to by the relevant URL . | |
CSS2 | None | CSS2 pseudo-class selector @page:first sets the page container first The style used by the page. Only used for @page rules | |
CSS2 | None | CSS2 pseudo-class selector @page: left sets the style used by all pages whose page container is located to the left of the gutter. Only used for @page rules | |
CSS2 | None | CSS2 is the object selector @page: right sets the style used for all pages whose page container is located to the right of the gutter. Only for @page rules |
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