The class name selector is not new to css3. The class name selector is used to select elements with specified classes. The syntax is ".class{css code;}"; the class name selector is in css3. It has been used before, and it is not new to CSS3. New selectors in CSS3 include attribute selectors, structural pseudo-class selectors, etc.
The operating environment of this tutorial: Windows 10 system, CSS3&&HTML5 version, Dell G3 computer.
Class name selector
Class selector
Use the class attribute to call the class class
Example:
<p class="one">类选择器</p>
.one { color: yellow; }
The p tag class name here is called one, which is used when CSS adds styles to it. One (his class name) selects it. This is the class selector.
Extended knowledge: css3 new selector
Attribute selector
input[value] { }(input and With value attribute)
input[type=text] {} {The value of the input attribute is text and needs to be changed}
- ##div[ class^=icon] { } (Select elements that are first a div and then have a class attribute and the attribute value must start with icon)
- section[class$=data] {} (Select The class name ends with data)
- ul li:first-child { } (select the first child in ul A child li)
- ul li:last-child { } (Select the last child li in ul) ##ul li:nth-child(2) { } (Select the second child li in ul)
- ul li:nth-child(6) { } (Select the second child in ul The sixth child is small li)
- ul li:nth-child(even/2n) { } (Select all even-numbered children)
- ul li:nth-child(odd/2n 1) { } (Select all odd-numbered children)
- ol li:nth-child(n ) { } (Start from 0 and add 1 each time. Calculating backward must be n. It cannot be other letters. Select all children
- ul li:nth-child(n 5) { } (Select starting from the fifth child)
- ##ul li:nth-child(-n 5) { } (Select starting from the fifth child and counting forward)
- ul li:first-of-type { } (first child)
- ul li:last-of-type { } (last child child)
- ul li:nth-of-type(even) { } (even number of children)
- section div:nth-child( 1) { } (nth-child will arrange all the boxes with serial numbers. When executing, first look at: nth-child(1) and then go back and look at the previous div)
- section div:nth -of-type(1) { } (nth-of-type will arrange the boxes of the specified element by serial number; when executing, first look at the element specified by div and then go back to see: nth-of-type(1) which child)
- Pseudo element selector (not found on the page, often used for font labels) [Same as label selector, weight is 1]
- ::after inserts content after the element (in front of the inside of the parent box)
- Must have content attribute
- div::after { content: 'I';}
- .tudou:hover::before { } (When our mouse passes over the potato box, the before mask layer inside is displayed)
- Pseudo elements clear floating
- (Learning video sharing: css video tutorial
html video tutorial)
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