height of wrapper div to inside floated items?

I have a div 'a' ( simple div)

and div 'b' which is float:left;

I was wondering what is the correct method to set the height of 开发者_高级运维div 'a' to be a perfect wrapper for div 'b' ( in terms of height).

i know there are some options :

1)set 'a' : overflow:hidden ( it works).

2)set at the end of 'b' div with 'clear':both

• ) i would love to know more options ( besides fixed height to div 'a'...)

• ) and of course , what is the better way.

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@Royi Namir; there others mades like clearfix like this

css:

.clearfix:after {
    display: block;
    content: " ";
    clear: both;
    }

as per the better way clearfix & overflow:hidden both are better because you no need to write any extra markup in your html for every element.