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Master the is and where selectors: Create dynamic and interactive CSS layouts

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Release： 2023-09-08 16:55:57

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Master the is and where selectors: Create dynamic and interactive CSS layouts

Proficient in is and where selectors: Create dynamic and interactive CSS layouts

CSS is an indispensable part of front-end development, it can provide web pages Provides various exquisite design effects. Among them, selectors are one of the cores of CSS, which can help us select elements on the page and style them. This article will introduce two commonly used CSS selectors: is and where. Through their flexible use, we can create a more dynamic and interactive CSS layout.

1. is selector

The is selector is a new selector introduced in CSS Level 4. It can select specific elements based on attribute matching of the elements. The is selector takes one or more selectors as arguments, separated by commas. For example:

nav.is-active,
.header.is-active {
  background-color: #ff0000;
  color: #ffffff;
}

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In the above code, the selectors nav.is-active and .header.is-active represent the selection of nav elements and .header elements with class is-active. When these elements are selected, the corresponding styles are applied, including a background color of red and a font color of white.

With the is selector, we can select elements based on different attribute values to achieve dynamic style switching effects. For example, in a navigation bar, we can add the is-active class based on the currently selected navigation item, and then use the is selector to add different styles to different navigation items to highlight the currently selected item.

2. Where selector

The where selector is also a new selector introduced in CSS Level 4. It can select elements based on specified selector conditions, similar to the logical operations of CSS. symbol. For example:

div:where(.is-active) {
  background-color: #ff0000;
  color: #ffffff;
}

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In the above code, the selector div:where(.is-active) means to select the div element with class is-active. When the element is selected, the corresponding styles are applied, including the background color being red and the font color being white.

With the where selector, we can more flexibly select elements with specific conditions, such as selecting the first child element or selecting the last child element, and selecting based on the position of the element in the document flow, etc. . In this way, we can set corresponding styles according to the position and status of elements to achieve a more dynamic and interactive layout effect.

3. Sample Application

The following is a simple example that demonstrates how to use the is and where selectors to create dynamic and interactive CSS layouts.

<!DOCTYPE html>
<html>
  <head>
    <style>
      div:where(.is-active) {
        background-color: #ff0000;
        color: #ffffff;
      }
      
      nav.is-active,
      .header.is-active {
        background-color: #ff0000;
        color: #ffffff;
      }
      
      .nav-item:hover {
        background-color: #0000ff;
        color: #ffffff;
      }
    </style>
  </head>
  <body>
    <div class="is-active">Div 1</div>
    <div>Div 2</div>
    
    <nav class="is-active">Nav 1</nav>
    <nav>Nav 2</nav>
    
    <div class="header is-active">Header 1</div>
    <div class="header">Header 2</div>
    
    <ul class="nav-list">
      <li class="nav-item">Item 1</li>
      <li class="nav-item">Item 2</li>
      <li class="nav-item">Item 3</li>
    </ul>
  </body>
</html>

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Through the above code, you can see that when the element with the class name is-active is selected, its background color and font color will turn red; at the same time, when the mouse hovers over the class name nav- When the item element is on, the background color and font color will turn blue.

This example shows how to add specific styles to elements based on their status and attributes to achieve a dynamic and interactive CSS layout effect.

Summary:

Through the is selector and where selector, we can select and style elements more flexibly, thereby creating a more dynamic and interactive CSS layout. Their introduction provides more choices and possibilities for front-end development, allowing us to better meet different design needs and user interaction experiences. For more information on the usage and examples of the is selector and where selector, you can consult relevant documents and tutorials to master their application skills and add more creativity and highlights to your page design and layout.

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