Talk about CSS floating issues_html/css_WEB-ITnose-HTML Tutorial-php.cn

Talk about CSS floating issues_html/css_WEB-ITnose

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Release： 2016-06-24 11:48:11

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How floats work

Floated elements break away from the document flow and do not occupy space. A floating element stays when it hits the border that contains it or the floating element's border.

Possible problems caused by floating elements

1. The height of the parent element cannot be expanded, affecting elements at the same level as the parent element

2. Non-floating elements at the same level as the floating element will follow it

3. If the first element is not floated, the elements before it also need to be floated, otherwise it will affect the display structure of the page

What is the solution for clearing floats?

Generally speaking, there are three ways.

1. Use empty tags to clear floating tags

Add an empty tag after all floating tags and define the CSS property clear:both

Comparison chart: The div is not stretched

Just add an empty tag. The disadvantage is that it adds an unsemantic tag

<style type="text/css">    html,body,div{ margin: 0;padding: 0;}      .box{border: 1px solid #333;}      p{border: 1px dotted #333;}      .box img{float: left;}      .box p{float: left;}      .cb{clear: both;}    </style></head><body><div class="box"><img src="1.jpg" width="50px" height="50px">    <p>one</p><!--在这里增加    <div class="cb"></div> --></div></body>

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Of course, if You don’t need to float the element behind the floated element. You can add clear:both to it, which is also good.

2. Use overflow

to add CSS attributes to the parent element tag containing the floating element, overflow:hidden or auto; zoom:1 , where zoom:1 is used Compatible with IE6, the purpose is to trigger hasLayout

3. Use the after pseudo-object to clear the float.

But this method is only applicable to non-IE browsers. Also note that when using it, remember to set height:0 for the pseudo object that needs to clear the floating element; otherwise the object will be higher than the actual value. out a number of pixels.

<head><style>    html,body,div{ margin: 0;padding: 0;}      .box{border: 1px solid #333;}      p{border: 1px dotted #333;}      .box img{float: left;}      .box p{float: left;}      .cb{clear: both;}            .clearfix{display: inline-block; /*zoom:1;*/ } /* for IE  ; or use zoom:1 to trigger the hasLayout; */      .clearfix:after{content: "."; display: block; height: 0; visibility: hidden;clear: both;}    </style></head><body><div class="box clearfix"><img src="1.jpg" width="50px" height="50px">    <p>one</p></div></body>

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4. Even the parent element of the floating element is also floated, but the whole thing is floated again, so it is not recommended~

5. Another way is to directly add attributes to floating elements display: table; You have to trigger hasLayout, add zoom:1 or display:inline-block