Are you familiar with these five common absolute positioning methods?

Five common absolute positioning methods, do you know them all?

Absolute positioning is a commonly used positioning method in CSS, which allows an element to be positioned relative to its nearest positioned ancestor element. In this article, we'll cover five common ways of absolute positioning and provide specific code examples for each.

1. top, right, bottom, left positioning

The most common absolute positioning method is to use the top, right, bottom and left attributes to position elements. By specifying the values ​​of these properties, we can control the position of an element relative to its parent element.

<div style="position: relative;">
  <div style="position: absolute; top: 10px; right: 10px;">我在右上角</div>
</div>

The above code will position the second div element at the top right corner of its parent element, 10 pixels from the top and right.

2. Percent positioning

In addition to using specific pixel values, we can also use percentages to position elements. Percent positioning is relative to the width and height of the parent element. For example, we can use 50% to center the element horizontally.

<div style="position: relative;">
  <div style="position: absolute; left: 50%;">我水平居中</div>
</div>

The above code will position the second div element horizontally centered on its parent element.

3. Offset positioning

Offset positioning is to position an element by specifying its offset from its original position. We can use negative values ​​to move an element up or to the left, and positive values ​​to move an element down or to the right.

<div style="position: relative;">
  <div style="position: absolute; top: -20px; left: -20px;">我向上和向左偏移了</div>
</div>

The above code will move the second div element up and to the left by 20 pixels.

4. Cascading positioning

Cascading positioning refers to controlling the stacking order of elements by specifying the z-index attribute of the element. The larger the z-index value of an element, the higher it is displayed.

<div style="position: relative;">
  <div style="position: absolute; top: 10px; left: 10px; z-index: 1;">我在上面</div>
  <div style="position: absolute; top: 20px; left: 20px; z-index: 2;">我在下面</div>
</div>

The above code displays the second div element on top of the first div element.

5. Fixed positioning

Fixed positioning means that the element is positioned relative to the position of the browser window. No matter how the scroll bar moves, the element will remain in a fixed position.

<div style="position: fixed; top: 10px; right: 10px;">我固定在右上角</div>

The above code will pin the element to the upper right corner of the browser window.

By mastering these five common absolute positioning methods, we can more flexibly control and layout elements in web pages. I hope this article can help you understand and use CSS absolute positioning.

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