css don’t forget to clear floating clear:both_Experience exchange

Clear with empty tag
.clr {clear: both;}

 

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Use the overflow attribute
#layout {overflow:auto; zoom:1;}

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Use :after (non-IE browser)
#layout:after{
display: block;
clear: both; content: "";
visibility:hidden; height: 0;
}

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Note: There are a few points to note when using :after, set the height to zero ( height: 0;); content is required, but its value can be empty