How to use CSS Viewport units to adjust element position based on screen size-CSS Tutorial-php.cn

How to use CSS Viewport units to adjust element position based on screen size

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Release： 2023-09-13 13:18:31

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如何使用 CSS Viewport 单位来实现根据屏幕尺寸调整元素位置的技巧

How to use CSS Viewport units to adjust the position of elements according to the screen size

In web development, we often encounter the need to adjust the position of elements according to different screen sizes. The need to adjust the position and size of elements. To achieve this goal, CSS Viewport units are widely used. Viewport units are units relative to the size of the browser window. By using them, we can dynamically adjust the position of elements based on the screen size, thereby providing a better user experience.

1. Understanding Viewport units

There are four types of Viewport units: vw (percentage of window width), vh (percentage of window height), vmin (the smaller of window width and height) as a percentage) and vmax (a percentage of the larger of the viewport width and height).

Take vw as an example, assuming the window width is 1000px, if we set the width of an element to 50vw, its width will be 500px (half of 1000px), regardless of the user's screen size .

2. Example demonstration

The following uses an example to demonstrate how to use the Viewport unit to adjust the position of the element.

html Code:

<!DOCTYPE html>
<html>
  <head>
    <style>
      .container {
        width: 100vw;
        height: 100vh;
        display: flex;
        justify-content: center;
        align-items: center;
      }
      
      .box {
        width: 50vw;
        height: 50vh;
        background-color: #ff0000;
      }
    </style>
  </head>
  <body>
    <div class="container">
      <div class="box"></div>
    </div>
  </body>
</html>

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In the above code, we create a div element named "container" and set the width and height to 100vw and 100vh, which means it will fill up the entire screen. Next, a div element named "box" is added to the container, and the width and height are set to 50vw and 50vh, and the background color is red.

Running the above code, we can see that no matter how big the screen size is, the box element is always displayed in the center, and its width and height are adaptively adjusted according to the screen size.

3. More application scenarios

In addition to the above basic examples of adjusting the position and size of elements, the Viewport unit can also be used for more complex application scenarios. For example, you can use vw units to set the size of responsive images, or use vh units to achieve a full-screen scrolling effect that adapts to the screen height.

In addition, you can also combine CSS Media Queries and Viewport units to adjust different layouts and styles according to the screen size. For example, you can hide an element on a small-screen device and show it on a large-screen device, and you can use Viewport units to adjust the element's size and position.

Summary

CSS Viewport units provide a flexible way to adjust element position and size based on screen size. We can use vw, vh, vmin and vmax units to set the width, height and position of elements to provide a better user experience. Whether it is a simple centered layout or a complex responsive design, the Viewport unit can help us achieve flexible layout and style effects.

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