Not included. CSS selectors include: 1. Tag selector, which locates specific HTML elements through the element name of the HTML page; 2. Class selector, which locates specific HTML elements through the value of the class attribute of the HTML element; 3. ID selector, which Locate specific HTML elements through the value of the id attribute of the HTML element; 4. The wildcard selector "*" can refer to all types of tag elements, including custom elements; 5. The attribute selector uses the existing attribute name of the HTML element or attribute value to locate a specific HTML element.
The operating environment of this tutorial: Windows 7 system, CSS3&&HTML5 version, Dell G3 computer.
CSS selectors do not include "hypertext tag selectors", but include class selectors, tag selectors, ID selectors, attribute selectors, pseudo-class selectors, etc.
What is a css selector?
Style is the smallest syntax unit of CSS. Each style contains two parts: selector and Statement (rule), as shown below.
1. Selector (Selector)
The selector consists of the id, class attribute or element name itself of the HTML element and some Special symbols are used to specify which HTML element to define the style for. For example, the selector p means to define the style for all
tags in the page;
2. Declaration
There can be one or countless declarations. These declarations tell the browser how to render the object specified by the selector. All declarations are placed within a pair of curly braces { }, and then the entire declaration is placed immediately after the selector.
The statement must include two parts: attributes and attribute values, and use a semicolon to mark the end of a statement. The semicolon can be omitted for the last statement in a style.
Attribute: The style name you want to set for the HTML element, consisting of a series of keywords, such as color, border, font, etc., in CSS Provides many attributes, which you can view through the W3C official website;
Value: consists of a numerical value and a unit or keyword, used to control the display effect of a certain attribute, such as the value of the color attribute It can be red or #F1F1F1 etc.
#What are the css selectors?
We start with an Html structure
<div id="box">
<div class="one">
<p class="one_1">
</p >
<p class="one_1">
</p >
</div>
<div class="two"></div>
<div class="two"></div>
<div class="two"></div>
</div>Commonly used selectors for css are:
:link ：选择未被访问的链接 :visited：选取已被访问的链接 :active：选择活动链接 :hover ：鼠标指针浮动在上面的元素 :focus ：选择具有焦点的 :first-child：父元素的首个子元素
:first-letter ：用于选取指定选择器的首字母 :first-line ：选取指定选择器的首行 :before : 选择器在被选元素的内容前面插入内容 :after : 选择器在被选元素的内容后面插入内容
[attribute] 选择带有attribute属性的元素 [attribute=value] 选择所有使用attribute=value的元素 [attribute~=value] 选择attribute属性包含value的元素 [attribute|=value]：选择attribute属性以value开头的元素
:first-of-type 表示一组同级元素中其类型的第一个元素 :last-of-type 表示一组同级元素中其类型的最后一个元素 :only-of-type 表示没有同类型兄弟元素的元素 :only-child 表示没有任何兄弟的元素 :nth-child(n) 根据元素在一组同级中的位置匹配元素 :nth-last-of-type(n) 匹配给定类型的元素，基于它们在一组兄弟元素中的位置，从末尾开始计数 :last-child 表示一组兄弟元素中的最后一个元素 :root 设置HTML文档 :empty 指定空的元素 :enabled 选择可用元素 :disabled 选择被禁用元素 :checked 选择选中的元素 :not(selector) 选择与 <selector> 不匹配的所有元素
[attribute*=value]：选择attribute属性值包含value的所有元素 [attribute^=value]：选择attribute属性开头为value的所有元素 [attribute$=value]：选择attribute属性结尾为value的所有元素
css basic selector and priority
css basic selector
| Description | |
|---|---|
| Also known as type selector, this basic selector is through the elements of the HTML page Name locates specific HTML elements. If the type selector is used alone, it will locate all elements with this element name in the current HTML page. | |
| locates specific HTML elements through the value of the class attribute of the HTML element. The usage of this basic selector is in the form | .Class name. |
| is similar to the class selector. They match HTML elements based on a certain attribute. The class selector matches the class selector, while The ID selector matches the id attribute. It is worth noting that the ID attribute is the only non-repeatable in the entire page. | |
是一个星号（*），这个选择器是一个特殊的标签选择器，它可以指代所有类型的标签元素，包括自定义元素，以及
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