What are relational selectors?

Relational selectors include "descendant selector", "child element selector", "adjacent sibling selector" and "universal sibling selector": 1. Descendant selector, through the descendant relationship of the element to select elements; 2. Child element selector, selects elements through the element's parent-child relationship; 3. Adjacent sibling selector, selects elements through the element's adjacent sibling relationship; 4. Universal sibling selector, selects elements through the element's brothers relationship to select elements.

# Operating system for this tutorial: Windows 10 system, Dell G3 computer.

Relational selectors are used to select relationships between elements. The following are several common relational selectors:

1. Descendant selectors (Descendant Selector): Select elements through their descendant relationships.

div p {  
color: blue;
}

In the above example, all

elements located inside

elements will be selected and the text color will be set to blue.

2. Child Selector: Select elements through their parent-child relationship.

div > p {  
font-weight: bold;
}

In the above example, all

elements directly located inside the

element will be selected and the font will be bold.

3. Adjacent Sibling Selector: Select elements through their adjacent sibling relationships.

h1 + p {  
color: red;
}

In the above example, the

element immediately following the

element will be selected and the text color will be set to red.

4. General Sibling Selector: Select elements through their sibling relationship.

h1 ~ p {  
font-style: italic;
}

In the above example, all

elements located after the

element will be selected and the font style will be set to italic.

These relational selectors can help us select elements more accurately and apply styles based on the specific relationship between them. By rationally using relational selectors, we can flexibly control the style of elements on the page.

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