What is the use of style=“clear:both”?

Question

I happened to see a div which had the style clear:both ! What is the use of clear in style ?

<div style="clear:both">

Answer 1

clear:both makes the element drop below any floated elements that precede it in the document.

You can also use clear:left or clear:right to make it drop below only those elements that have been floated left or right.

+------------+ +--------------------+
|            | |                    |
| float:left | |   without clear    |
|            | |                    |
|            | +--------------------+
|            | +--------------------+
|            | |                    |
|            | |  with clear:right  |
|            | |  (no effect here,  |
|            | |   as there is no   |
|            | |   float:right      |
|            | |   element)         |
|            | |                    |
|            | +--------------------+
|            |
+------------+
+---------------------+
|                     |
|   with clear:left   |
|    or clear:both    |
|                     |
+---------------------+

Answer 2

只需添加到RichieHindle的回答，请Floatutorial ，其中详细介绍了如何CSS浮动和结算工程。

Answer 3

When you use float without width, there remains some space in that row. To block this space you can use clear:both; in next element.