CSS absolute and position Positioning

Absolute: absolute positioning. CSS is written as "position: absolute;". Its positioning is divided into two situations:

1. If top, right, bottom, and left are not set, the "content region original point" of the parent level is the original point by default.

2. If top, right, bottom, and left are set, the following two situations are involved:

(1 ). the parent class does not have the position attribute. In the browser, the upper left corner (that is, the body) is the "original coordinate point" for positioning. The position is determined by the top, right, bottom, and left attributes. The green section in the preceding example is used.

(2) The parent level has the position attribute, and the "original coordinate point" of the parent level is the original point.

Relative: relative positioning. CSS is written as "position: relative;". The original point is referred to as the "original point of content area" of the parent level. If there is no parent level, the "original point of content area" of the body is the original point, the position is determined by the top, right, bottom, and left attributes, and can be opened up or occupied in height.