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What are the css descendant selectors?

青灯夜游

Jul 07, 2021 pm 02:59 PM

css

css descendant selectors include: 1. "Parent element * {}", find all descendant elements from the parent element. 2. "Parent Children {}" is to find the specified child element from the parent element; 3. "Parent Child 1 Child 2 {}" is to find the child 1 from the parent, and then from the child Generation 1 finds descendant 2.

What are the css descendant selectors?

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

The descendant selector is also called the containing selector.

The descendant selector can select elements that are descendants of an element.

Descendant selector concentrated form:

1, Parent * {}Find all descendants from Parent.

2, parent generation child1{} is to find child1 from the parent generation or parent generation child2{} is to be found from the parent generation Offspring 2.

3, Parent Generation Child 1 Child 2{} This is to find Child 1 from Parent Generation, and then find Child 2 from Child 1.

The first form: Although all are selected, * has a lower priority.

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8" />
        <title></title>
        <style>
            div{
                padding: 20px;
                background: rgba(255,0,0,0.2);     //这是给它一个红色，透明度为0.2
            } 
        .a *{
                border: 2px solid black;  //这里是选中类a的所有后代
            }
        </style>
    </head>
    <body>
        <div class="a">a
            <div class="b">b
                <div class="c">c</div>
            </div>
        </div>
    </body>
</html>

Second form:

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8" />
        <title></title>
        <style>
            div{
                
                padding: 20px;
                background: rgba(255,0,0,0.2);
            }
            
        .a .b{
                border: 2px solid black; //同理这里选择 .c 也是可以的因为他们都是 .a 的后代。
            }
            
            
        </style>
    </head>
    <body>
        <div class="a">a
            <div class="b">b
                <div class="c">c</div>
            </div>
        </div>
    </body>
</html>

The third form: it cannot select .b and .c at the same time, only .c.

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8" />
        <title></title>
        <style>
            div{
                
                padding: 20px;
                background: rgba(255,0,0,0.2);
            }
            
            .a .b .c{
                border: 2px solid black;
            }
            
            
        </style>
    </head>
    <body>
        <div class="a">a
            <div class="b">b
                <div class="c">c</div>
            </div>
        </div>
    </body>
</html>

Another thing to note is the following code: a p is nested in a p with a class name of c, and a p with a class name of c is nested in it. At this time, it will also be selected

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8" />
        <title></title>
        <style>
            div{
                
                padding: 20px;
                background: rgba(255,0,0,0.2);
            }
            
            .a .b .c{
                border: 2px solid black;
            }
            
            
        </style>
    </head>
    <body>
        <div class="a">a
            <div class="b">b
                <div class="c">c
                <div>
                    <div class="c">span</div>
                </div>
                </div>
            </div>
        </div>
    </body>
</html>

（Learning video sharing: css video tutorial）

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