MicroTut: Centering a Div Both Horizontally And Vertically
Created by Martin Angelov on Mar 5th, 2010
While building web page layouts, you’ve probably been faced with a situation where you need to center a div both horizontally and vertically with pure CSS. There are more than a few ways to achieve this, and in this MicroTut I am going to show you my favorite involving CSS and jQuery.
But first, the basics:
Horizontal centering with CSS
It is as easy as applying a margin to a div:
.className{
margin:0 auto;
width:200px;
height:200px;
}
To center a div only horizontally, you need to specify a width, and an auto value for the left and right margins (you do remember the shorthand declarations in CSS don’t you?). This method works on block level elements (divs, paragraphs, h1, etc). To apply it to inline elements (like hyperlinks and images), you need to apply one additional rule – display:block.
Horizontal and vertical centering with CSS
Center a div both horizontally and vertically with CSS is a bit more tricky. You need to know the dimensions of the div beforehand.
.className{
width:300px;
height:200px;
position:absolute;
left:50%;
top:50%;
margin:-100px 0 0 -150px;
}
By positioning the element absolutely, we can detach it from its surroundings and specify its position in relation to the browser window. Offsetting the div by 50% from the left and the top part of the window, you have its upper-left corner precisely at the center of the page. The only thing we are left to do is to move the div to the left and to the top with half its width and height with a negative margin, to have it perfectly centered.
Horizontal and vertical centering with jQuery
As mentioned earlier – the CSS method only works with divs with fixed dimensions. This is where jQuery comes into play:
$(window).resize(function(){
$('.className').css({
position:'absolute',
left: ($(window).width() - $('.className').outerWidth())/2,
top: ($(window).height() - $('.className').outerHeight())/2
});
});
// To initially run the function:
$(window).resize();
The functionality is inserted into a $(window).resize() statement, which is executed every time the window is resized by the user. We use outerWidth() and outerHeight(), because unlike from the regular width() and height(), they add the padding and the border width to the returned size. Lastly, we simulate a resize event to kick center the div on page load.
The benefit of using this method, is that you do not need to know how big the div is. The main disadvantage is that it will only work with JavaScript turned on. This however makes it perfect for rich user interfaces (such as facebook’s).
Be sure to share your favorite methods in the comment section.
Related:
21 Responses
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Loving the new Micro Tuts section. Keep up the good work!
Cool concept, looking forward to more Micro Tuts.
Nice tut! Loving how this is achievable in both CSS and jQuery so that you’re not boxing yourself into one solution.
I want to see more like these!
Except that you *can* center things both horizontally and vertically using just CSS, and without knowing the container’s size:
http://benalman.com/code/test/css-centering.html
(the jQuery used in this example is to simply show that you don’t need to know the size of the element to keep it centered)
- Ben
Thanks for the comments fellas!
@ “Cowboy” Ben Alman
Interesting experiment. Kinda too hackish for me but there you have it – centering a div with css IS possible without knowing its size.
Thanks for vertical centering tut!
Hi Martin, I’m fan of your MicroTut section now. It’s very helpful. You are doing a good job, friend!
Great example Martin. One thing i noticed about this example is that when there is a vertical scroll on the page the element is centered to the position of the whole document. This can be fixed easily by replacing the document with window like:
left: ($(window).width() – $(‘.className’).outerWidth())/2,
top: ($(window).height() – $(‘.className’).outerHeight())/2
Micro Tuts section is a great idea, Always interesting to discover new css techniques.
@ Parag
Thank you for noticing that! I fixed it in both the article and the demonstration.
For those of you reading this comment, I had wrongly used $(document).width() and $(document).height() instead of $(window).width() and $(window).height().
The difference is that the $(document) methods return the size of the entire document, and the $(window) ones return only the dimensions of the browser window (the document can expand way beyond the browser window).
The example pages didn’t have content which overflowed outside of the window, so the error went unnoticed.
I prefer the jquery workaround .
This is an cool tut. Very useful ! Thank`s a lot, i know for sure that i`l use this on few websites!
Brilliant, just what I’ve always wanted! Thanks to @smashingmag
Great micro tut
however, i use a more dynamic solution for the second example. instead of giving the div a fix width and height and taking the half of the values as negative margin, i’m used to giving the div a % width, lets say: 20%
and a position: absolute; with left: 40%;.
Its quite the same…
thanks again
and keep up the good work
that’s a neat little tut.
want more
I love this site! Very good tutorial laying out the differences between the two methods. I think, like most, that jQuery is the easiest solution but having to account for those 5% that don’t have scripting turned on can be frustrating.
Great tutorial, tks!
I suggest in this section, a tutorial about how create equal height columns. I google a solution, but not the best.
Congratulations.
Excellent.
can i use your demos in my website?
All your tuts are awesome…i like very much..Explanation is very understandable…Keep on………..
Just what I was looking for. Thanks!