Clearfix VS Overflow

ClearFix vs Overflow

The only time you should bother using the "clearfix" method that inserts invisible content to clear is if you need an element to be visible when it overflows the element you're applying it to, otherwise triggering hasLayout + overflow is golden.

Note that in IE7 overflow hidden triggers hasLayout. Not sure about IE8.

#wrapper { width:80em; overflow:hidden; }

The method above will work fine in most all cases unless you need say, #header to overflow past #wrapper..

#wrapper { width:80em; position:relative; }
#wrapper:after {  content:"."; clear:both; display:block; height:0; visibility:hidden; }
#header { position:absolute; top:-15px; left:-15px; }

What is the different between clearfix hack and overflow:hidden vs overflow:auto?

Ed Eliot has written the definitive guide on the subject.

clearfix' OR 'overflow: hidden' Which is better for multiple listing?

Both methods achieve similar results, but in some cases, one may be more advantageous than the other.

The use of overflow: {auto|hidden} creates a new block formatting context and that has implications for how margins and paddings are contained within the parent elmement. For example, with a new block formatting context, some margins will not collapse as you might expect.

With a clearing element (either in the DOM or as a pseudo element), margins collapse as expected.

Beyond this distinction, it is hard to recommend one method over the other.

Comment: Adding Classes to li

Adding an additional class name to the li elements will not significantly slow down the page load time as a result of the work the broswer does to parse the page and apply the stylesheets.

Unless you have a complex web page with thousands of CSS rules, I don't think that you need to be too concerned about browser performance.

What is more relevant to the average web developer is that having a page that is marked up with numerous classes can make maintenance more difficult. Keeping stylesheets organized is a skill that you develop with experience.

What methods of ‘clearfix’ can I use?

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

Modern Clearfix Solutions

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.

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.

⋮

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.

"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."

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;
}

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.

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

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.

what is the difference between 'overflow and clear to clear float?

Strange comparison since overflow and clear are completely unrelated. Unless I misunderstood your question. In which case, please rephrase so that we can clarify better.

Anyhow, overflow controls the any excess outside of the width of an element.

The overflow property specifies what happens if content overflows an element's box.

If you have a div with containing a large image and you want to restrict the image to not exceed the width of that container, overflow will do just that by giving it a hidden value. If you want it to scroll after a certain width or height, the scroll value will activate the scrollbars to allow you to do so.

Clear on the other hand, resets the floats.

The clear property specifies on which sides of an element floating elements are not allowed to float.

This is particularly helpful in responsive design to center an item that has been floated to the right in larger displays but you want to reset it to the native left position for smaller devices. Of course, the use of clear can be determined by other factors according to your need of it.

The example above mentioned would look like this

<div class="box">
  <button class="right">Hello</button>
</div>

CSS

.right{
   float: right;
}
@media (max-width: 420px){
   .right{
       clear: right;
   }
}

960 grid's clearfix vs HTML5 Boilerplate's clearfix - What's the difference?

The only difference is that 960's has this inside .clearfix:before, .clearfix:after:

visibility: hidden;
width: 0;

Other than that, they are identical.

height: 0; overflow: hidden should remove the need for any other declarations to hide the pseudo-elements.

My theory is that the HTML5 Boilerplate folks have stringently verified that those two extra declarations are not required for any browser and then removed them.

Is clearfix deprecated?

You can pretty much use overflow: hidden all the time.

But, there are exceptions. Here's an example of one:

Overflowing a container div horizontally but not vertically

The question there was:

There's a fixed height on this: http://jsfiddle.net/je8aS/2/
Without the fixed height: http://jsfiddle.net/thirtydot/je8aS/5/
How to clear the floats without using a fixed height?
overflow: hidden doesn't work: http://jsfiddle.net/thirtydot/je8aS/6/
You have to use some other method of clearing floats, such as clear: both:

http://jsfiddle.net/je8aS/3/
The clearfix class also works: http://jsfiddle.net/thirtydot/je8aS/11/

Here's a more important example of when you can't use overflow: hidden:

http://fordinteractive.com/misc/overflow/

That's not to say that clearfix is the only alternative - display: inline-block cleanly fixes that example:

http://jsbin.com/ubapog

What is a clearfix?

If you don't need to support IE9 or lower, you can use flexbox freely, and don't need to use floated layouts.

It's worth noting that today, the use of floated elements for layout is getting more and more discouraged with the use of better alternatives.

display: inline-block - Better
Flexbox - Best (but limited browser support)

Flexbox is supported from Firefox 18, Chrome 21, Opera 12.10, and Internet Explorer 10, Safari 6.1 (including Mobile Safari) and Android's default browser 4.4.

For a detailed browser list see: https://caniuse.com/flexbox.

(Perhaps once its position is established completely, it may be the absolutely recommended way of laying out elements.)

A clearfix is a way for an element to automatically clear its child elements, so that you don't need to add additional markup. It's generally used in float layouts where elements are floated to be stacked horizontally.

The clearfix is a way to combat the zero-height container problem for floated elements

A clearfix is performed as follows:

.clearfix::after {
   content: " "; /* Older browser do not support empty content */
   visibility: hidden;
   display: block;
   height: 0;
   clear: both;
}

Or, if you don't require IE<8 support, the following is fine too:

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

Normally you would need to do something as follows:

<div>
    <div style="float: left;">Sidebar</div>
    <div style="clear: both;"></div> <!-- Clear the float -->
</div>

With clearfix, you only need the following:

<div class="clearfix">
    <div style="float: left;" class="clearfix">Sidebar</div>
    <!-- No Clearing div! -->
</div>

Read about it in this article - by Chris Coyer @ CSS-Tricks

Clearfix VS Overflow