CSS overlapping property analysis: position and float

CSS overlapping attribute analysis: position and float

In CSS, position and float are two commonly used overlapping attributes. They can change the layout behavior of elements and implement Various complex page effects. This article will analyze these two properties in detail and give specific code examples.

1. Position attribute

The position attribute defines the positioning method of the element. Commonly used values ​​​​are static, relative, absolute and fixed.

1. static: Default value, the elements are arranged normally according to the document flow, and there is no need to specify the top, right, bottom and left attributes.

2. relative: relative positioning, the element is positioned relative to its normal position. The positioning offset can be specified through the top, right, bottom and left attributes.

   Sample code:

   .box {
     position: relative;
     top: 10px;
     left: 20px;
   }

3. absolute: Absolute positioning, the element is removed from the document flow and positioned relative to its nearest non-statically positioned ancestor element. If there are no non-statically positioned ancestor elements, they are positioned relative to the browser window.

   Sample code:

   .box {
     position: absolute;
     top: 50px;
     right: 100px;
   }

4. fixed: fixed positioning, the element is positioned relative to the browser window and does not scroll with the scroll bar.

   Sample code:

   .box {
     position: fixed;
     bottom: 20px;
     left: 10px;
   }

2. Float attribute

The float attribute defines the floating method of the element. Commonly used values ​​​​are left, right and none.

1. left: The element floats to the left, out of the document flow, and other elements will surround it.

2. right: The element floats to the right, out of the document flow, and other elements will surround it.

   Sample code:

   .box {
     float: left;
   }

3. none: Default value, elements do not float and are arranged normally according to the document flow.

3. The difference and connection between position and float

1. Same points:

   • Both can realize the positioning of elements and layout changes.
   • When using both, the element breaks away from the document flow and no longer occupies the position of the normal flow.

2. Difference:

   • The position attribute does not change the box model of the element. When set to absolute or fixed, the element does not occupy a position in the document flow. , will not affect the layout of other elements. The float attribute will change the box model of the element, and the floating element will be surrounded by other elements.
   • When using the position attribute, you can specify the specific position of the element through the top, right, bottom and left attributes. When using the float attribute, you can only specify the floating direction of the element.
   • The position attribute can implement more complex layouts, such as cascading layout, absolute positioning, etc. The float attribute is more used to implement text wrapping pictures, multi-column layout, etc.

To sum up, position and float are commonly used overlapping attributes in CSS, and they can achieve various complex page layout effects. Reasonable use of these two attributes can make the page layout more flexible and beautiful.

I hope this article will help you understand the position and float attributes, and provide you with a reference for using these two attributes in actual development.

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