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What pseudo-classes are added to html5/css3

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Release： 2023-01-06 11:16:10

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The new pseudo-classes are: ":first-child", ":last-child", ":nth-child(n)", ":link", ":visited", ":active" ”, “:hover”, “:focus”, “:not()”, etc.

What pseudo-classes are added to html5/css3

The operating environment of this tutorial: Windows 7 system, CSS3&&HTML5 version, Dell G3 computer.

Structural pseudo-class selector

:first-child The first child node, :last-child The last child node, :nth-child(n) The nth child Node, :nth-last-child(n) The nth child node from the last, :only-child The only child node

:nth-child(n), :nth-last-child(n) and Some special usages limit the selection through things in brackets:

1. odd/event: the odd/even element

2. xn y: the xn y element

Without further ado, let’s talk about the code. The following is to set the pseudo-class selector for the li tag

<!DOCTYPE html>
<html>
  <head>
    <title></title>
    <style type="text/css">
      li:first-child {
        border: 1px solid black;
      }

      li:last-child {
        background-color: #aaa;
      }

      li:nth-child(2) {
        color: #888;
      }

      li:nth-last-child(2) {
        font-weight: bold;
      }

      span:only-child {
        font-size: 30pt;
      }
    </style>
  </head>
  <body>
    <ol>
      <li>oaaaaaaaaaaa</li>
      <li>obbbbbbbbbbb</li>
      <li>occccccccccc</li>
      <li>odddddddddd</li>
      <li>oeeeee</li>
      <li><span id="andorid"></span>saaaaaa啊飒飒</li>
    </ol>
  </body>
</html>

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You can see the difference Effect

UI element status pseudo-class selector

:link (element before being visited (usually only a hyperlink)), :visited(has been visited element (usually only a hyperlink), :active (the element being accessed is between the mouse click and release (usually only a hyperlink)), :hover (the element in the mouse hover state), :focus (Element that has received focus)

<!DOCTYPE html>
<html>
  <head>
    <title></title>
    <style type="text/css">
      .a {
        font-size: 50px;
      }
      .a:link {
        color: red;
      }
      .a:visited {
        color: grey;
      }
      .a:active {
        color: green;
      }
      .b {
        height: 40px;
        width: 200px;
      }
      .b:focus {
        background-color: blue;
      }
      .c {
        height: 40px;
        width: 60px;
      }
      .c:hover {
        background-color: skyblue;
      }
    </style>
  </head>
  <body>
    <a href="#" class="a">aaa</a>
    <form action="#">
      文本框:<input type="text" name="aaa" class="b" />
      <input type="submit" value="提交" class="c" />
    </form>
  </body>
</html>

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It started like this

When we click on the hyperlink

After clicking

#Next look at the text box. When we put the focus on the text box (that is, the input of the text box status), get: the style in focus

## Look at the button again, when the mouse hovers over the button, get: the style in hover (because the author wants to take a screenshot, one The cursor cannot be captured when taking a screenshot, so the cursor cannot be seen in the picture)

: The not() pseudo-class selector is equivalent to the subtraction of two selectors. , such as li:not(#a){} modifies all element blocks that match the li selector but do not match the id of a

Recommended learning:

css video tutorial

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