Let's talk about the differences between various positioning methods in CSS

CSS positioning is an important technology in web design. Through the positioning properties of CSS, we can control the position, size and display effect of elements in the web page. In CSS positioning, there are three common methods: absolute positioning, relative positioning and fixed positioning. Although all three methods can control the position and display effect of elements, there are still some differences between them. This article will introduce these differences in detail.

1. Absolute positioning

Absolute positioning refers to precise positioning of an element by specifying its position relative to its parent container (or ancestor container). When using absolute positioning, you need to pay attention to the following points:

1. The position of the absolutely positioned element will not affect the position of other elements, that is, other elements, whether they are up or down, left or right, or overlapping, will not be affected by the position of the element. Changed due to absolute positioning;

2. The position of an absolutely positioned element is positioned relative to its parent element (or ancestor element). If the parent element does not exist, it is positioned relative to the upper left corner of the document;

3. Absolutely positioned elements will break away from the document flow and no longer occupy their original position in the document. Therefore, when using absolute positioning, ensure that the elements do not overlap.

2. Relative positioning

Relative positioning refers to a way to achieve precise positioning by specifying the original position of an element to offset it. When using relative positioning, you need to pay attention to the following points:

1. The relative positioning element still occupies the original position, but the position can be fine-tuned as needed;

2. The relative positioning element The position is offset relative to its original position and will not affect the position of other elements;

3. The relatively positioned element still occupies the document flow, so it will not affect the position of other elements when using relative positioning.

3. Fixed positioning

Fixed positioning refers to fixing an element at a certain position on the screen. No matter the page is scrolled, the element will always be displayed at the original position. When using fixed positioning, you need to pay attention to the following points:

1. The position of the fixed positioning element will not affect the position of other elements, that is, other elements will not be affected by the position, whether they are up or down, left or right, or overlapping. Fixed positioning changes;

2. The position of fixed positioning elements is positioned relative to the browser window;

3. Fixed positioning elements will break away from the document flow and no longer occupy the original space in the document position, so when using fixed positioning, ensure that the elements do not overlap.

Summary:

It can be seen from the above three positioning methods that positioning in CSS is a very flexible method that can realize various forms of web page layout. The three positioning methods are similar in some aspects, but there are also differences in some aspects. In actual web design, we need to choose the appropriate positioning method according to the specific situation. Whether it is absolute positioning, relative positioning or fixed positioning, it can help us achieve positioning and layout in web design.

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