What methods of ‘clearfix’ can I use?

Question

I have the age-old problem of a div wrapping a two-column layout. My sidebar is floated, so my container div fails to wrap the content and sidebar.

<div id="container">
  <div id="content"></div>
  <div id="sidebar"></div>
</div>

There seem to be numerous methods of fixing the clear bug in Firefox:

• <br clear="all"/>
• overflow:auto
• overflow:hidden

In my situation, the only one that seems to work correctly is the <br clear="all"/> solution, which is a little bit scruffy. overflow:auto gives me nasty scrollbars, and overflow:hidden must surely have side effects. Also, IE7 apparently shouldn't suffer from this problem due to its incorrect behaviour, but in my situation it's suffering the same as Firefox.

Which method currently available to us is the most robust?

Answer 1

Depending upon the design being produced, each of the below clearfix CSS solutions has its own benefits.

The clearfix does have useful applications but it has also been used as a hack. Before you use a clearfix perhaps these modern css solutions can be useful:

• css flexbox
• css grid

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Modern Clearfix Solutions

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Container with overflow: auto;

The simplest way to clear floated elements is using the style overflow: auto on the containing element. This solution works in every modern browsers.

<div style="overflow: auto;">
  <img
    style="float: right;"
    src="path/to/floated-element.png"
    width="500"
    height="500"
  > 
  <p>Your content here…</p>
</div>

One downside, using certain combinations of margin and padding on the external element can cause scrollbars to appear but this can be solved by placing the margin and padding on another parent containing element.

Using ‘overflow: hidden’ is also a clearfix solution, but will not have scrollbars, however using hidden will crop any content positioned outside of the containing element.

Note: The floated element is an img tag in this example, but could be any html element.

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Clearfix Reloaded

Thierry Koblentz on CSSMojo wrote: The very latest clearfix reloaded. He noted that by dropping support for oldIE, the solution can be simplified to one css statement. Additionally, using display: block (instead of display: table) allows margins to collapse properly when elements with clearfix are siblings.

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

This is the most modern version of the clearfix.

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Older Clearfix Solutions

The below solutions are not necessary for modern browsers, but may be useful for targeting older browsers.

Note that these solutions rely upon browser bugs and therefore should be used only if none of the above solutions work for you.

They are listed roughly in chronological order.

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"Beat That ClearFix", a clearfix for modern browsers

Thierry Koblentz' of CSS Mojo has pointed out that when targeting modern browsers, we can now drop the zoom and ::before property/values and simply use:

.container::after {
    content: "";
    display: table;
    clear: both;
}

This solution does not support for IE 6/7 …on purpose!

Thierry also offers: "A word of caution: if you start a new project from scratch, go for it, but don’t swap this technique with the one you have now, because even though you do not support oldIE, your existing rules prevent collapsing margins."

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Micro Clearfix

The most recent and globally adopted clearfix solution, the Micro Clearfix by Nicolas Gallagher.

Known support: Firefox 3.5+, Safari 4+, Chrome, Opera 9+, IE 6+

.container::before, .container::after {
  content: "";
  display: table;
}
.container::after {
  clear: both;
}
.container {
  zoom: 1;
}

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Overflow Property

This basic method is preferred for the usual case, when positioned content will not show outside the bounds of the container.

http://www.quirksmode.org/css/clearing.html - explains how to resolve common issues related to this technique, namely, setting width: 100% on the container.

.container {
  overflow: hidden;
  display: inline-block;
  display: block;
}

Rather than using the display property to set "hasLayout" for IE, other properties can be used for triggering "hasLayout" for an element.

.container {
  overflow: hidden;
  zoom: 1;
  display: block;
}

Another way to clear floats using the overflow property is to use the underscore hack. IE will apply the values prefixed with the underscore, other browsers will not. The zoom property triggers hasLayout in IE:

.container {
  overflow: hidden;
  _overflow: visible; /* for IE */
  _zoom: 1; /* for IE */
}

While this works... it is not ideal to use hacks.

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PIE: Easy Clearing Method

This older "Easy Clearing" method has the advantage of allowing positioned elements to hang outside the bounds of the container, at the expense of more tricky CSS.

This solution is quite old, but you can learn all about Easy Clearing on Position Is Everything: http://www.positioniseverything.net/easyclearing.html

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Element using "clear" property

The quick and dirty solution (with some drawbacks) for when you’re quickly slapping something together:

<br style="clear: both" /> <!-- So dirty! -->

Drawbacks

• It's not responsive and thus may not provide the desired effect if layout styles change based upon media queries. A solution in pure CSS is more ideal.
• It adds html markup without necessarily adding any semantic value.
• It requires a inline definition and solution for each instance rather than a class reference to a single solution of a “clearfix” in the css and class references to it in the html.
• It makes code difficult to work with for others as they may have to write more hacks to work around it.
• In the future when you need/want to use another clearfix solution, you won't have to go back and remove every <br style="clear: both" /> tag littered around the markup.