Learn to use CSS absolute positioning to achieve layout effects

How to correctly use CSS absolute positioning to achieve layout effects requires specific code examples

Introduction:
In web design, layout is a very important link . Through reasonable layout, the web page can present a beautiful and neat visual effect and improve the user experience. In CSS, absolute positioning is one of the common ways of layout. This article will introduce how to correctly use CSS absolute positioning to achieve layout effects, and provide specific code examples for reference.

1. What is CSS absolute positioning
In CSS, absolute positioning is positioned relative to the closest positioned ancestor element. If the element has no positioned ancestor elements, it is positioned relative to the initial containing element. block to locate. Use absolute positioning to remove an element from the regular document flow and position it according to a specified position.

2. How to correctly use CSS absolute positioning to achieve layout effects

1. Set the parent element to relative positioning
   Before using CSS absolute positioning, you must first ensure that the parent element is positioned of. By setting the position attribute of the parent element to relative, you can make it a reference object for positioning, so that absolutely positioned child elements will be positioned relative to the parent element.

Sample code:

.parent {
  position: relative;
}

2. Set the child element to be absolutely positioned
   Set the position attribute of the child element that needs to be absolutely positioned to absolute, and specify the offset relative to the parent element through the top, right, bottom, left attributes. Shift amount.

Sample code:

.child {
  position: absolute;
  top: 50px;
  left: 100px;
}

3. Set the stacking order of positioned elements
   When using absolute positioning, if multiple elements overlap, you can pass z-index attribute to control their stacking order. z-indexThe value of the attribute is an integer. The larger the value, the higher the stacking order.

Sample code:

.child1 {
  position: absolute;
  top: 50px;
  left: 100px;
  z-index: 1;
}

.child2 {
  position: absolute;
  top: 50px;
  left: 100px;
  z-index: 2;
}

4. Use absolute positioning for layout
   By reasonably setting the position and size of child elements, you can use absolute positioning to achieve various complex layouts Effects, such as: centered layout, floating menu, carousel, etc.

Sample code 1: Centered layout

.parent {
  position: relative;
  width: 500px;
  height: 300px;
}

.child {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

Sample code 2: Suspension menu

.parent {
  position: relative;
  width: 100%;
  height: 100vh;
}

.child {
  position: absolute;
  top: 0;
  left: 0;
  width: 200px;
  height: 100%;
  background-color: #f5f5f5;
  z-index: 9999;
}

Sample code 3: Carousel image

.parent {
  position: relative;
  width: 800px;
  height: 400px;
  overflow: hidden;
}

.child {
  width: 100%;
  height: 100%;
  position: absolute;
  top: 0;
  transition: transform 0.5s ease-in-out;
}

Three , Summary
By correctly using CSS absolute positioning, various complex layout effects can be achieved. The key is to set the parent element to relative positioning and the child element to absolute positioning, and achieve the desired layout effect by appropriately setting the position, size and stacking order. I hope the above content will be helpful to you in using CSS absolute positioning to achieve layout effects.

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