Summary of pseudo-class selectors

Summary of pseudo-class selectors

1. Structural pseudo-class selector Structural pseudo-class selector
   It can select elements based on their position in the document. Such elements have a prefix ":"
   1 . The root element selector only works on bottom tags such as html. It is rarely used..

   :root

   The selection of all child elements needs to be more detailed. last-child The last one

   ul>li:only-child{ } Add the pseudo-class only-child Those with only one will affect the only child
   div>p: only-of type{ } Add the pseudo-class only-of-type to select the child element of the specified type. In fact, the function is similar to that of a single div>p

   

   ##Pseudo-classes need to add pre-selectors to limit the scope

   

   3. ul>li :nth-child(2) { } The second child element of li under ul

   ul>li:nth-last-child(2) { } …. The penultimate one

   Others:
   ##UI pseudo-class selector
   :enable
   :disable

   

html file
2. css file

   effect

   
   

   :checked The checked one takes effect

   html file

   ##css file

Hide the checked ones

:default The default takes effect, rarely used

css file

:valid Valid when legal

:invalid Valid when illegal

html file

css file

If you fill in the correct number, it will turn green.

:required The required part will take effect

optional No Required to take effect

html file

css file

a:link Acts on the text between a tags

input:focus

Switch Text input cursor, input box changes color

Other pseudo-class selectors

:not Inverse selection focuses on

Hyperlinks that do not contain baidu are red

:empty The effect is empty tags, a bit Like word's replacement of spaces means

html file

before replacement

css file

If you want not to affect some empty parts, you can specify such as

p:empty{ } Then the css will only affect Empty tag under p

After replacement

:lang

: target Positioning anchor point within the page, a certain position will take effect immediately

name or id Yes, the anchor can be set in any tag. As for the hyperlink, it is just a hyperlink. Here, enter #anchor name directly in the browser, and the effect is to press href The same after that.

##When testing, add "# anchor name" at the end

Effect (Actually, the anchor points are mostly on some very long pages, and they can be positioned at one point. And the edges turn red.)

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