Centering a div popup in the center of screen

Question

I have searched a lot for centering a div, both horizontally and vertically, this is the method given everywhere:

div {
position:fixed;
top:50%;
left:50%;
margin-left:(div width/2)
margin-top: (div height/2)
}

I just found a new solution to centering a div, both horizontally and vertically, by wrapping it inside a table. I've tested it in ie7 and above, plus other browsers.

Here is an example : http://jsbin.com/ocenok/2/

I was wondering that the first method is found everywhere on the internet, SO, etc. and requires beforehand knowledge of width and height, or is usually calculated via Javascript.

The table approach seems flawless, and requires neither javascript, nor fixed height/width.

Are there any drawbacks to the table approach ?

(I do not know the height/width of the div that I want to center.)

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Update (To make my question clearer) :

I myself hate using tables for non-tabular/layout data.

1. I know that what I want can easily be achieved using Javascript.
2. I figured I can achieve this using display:table, killing IE7 support.

But what I'm trying to understand is, that when I can achieve this using a single <table> element, what are the drawbacks, if any.

Checking Answers here and on similar questions, no one has recommended this method, even though it uses all valid HTML elements and syntax and rules.

If everyone is recommending to use javascript to handle presentation, even though it is easily possible using CSS, it must have some drawbacks.

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Code :

  <table>
    <tr>
        <td>
            <div>This is div that needs to be centered.</div>
        </td>
    </tr>
</table>

and then apply the following CSS

table {
    width:100%;
    height:100%;
    position:fixed;
    top:0;
    left:0;
}

table td {
    width : 100%;
    text-align: center;
}

div {
    width:100px;
    height:100px;
    background:pink;
  margin: 0 auto;
}

Answer 1

see the below function and change as per your needs

function positionLightboxImage() {
  var top = ($(window).height() - $('#lightbox').height()) / 2;
  var left = ($(window).width() - $('#lightbox').width()) / 2;
  console.log("The calculated position is:");
  console.log(top,left);
  $('#lightbox')
    .css({
      'top': top + $(document).scrollTop(),
      'left': left
    })
    .fadeIn();
  console.log('A jQuery selection:');
  console.log($('#lightbox'));
}

Updated answer HTML and CSS:

HTML:

<div id="outer"><div id="inner"></div></div>

CSS:

#outer {
  position: absolute;
  top: 50%;
  left: 0px;
  width: 100%;
  height: 1px;
  overflow: visible;
    background:red;
}

#inner {
  width: 300px;
  height: 200px;
  margin-left: -150px;  /***  width / 2   ***/
  position: absolute;
  top: -100px;          /***  height / 2   ***/
  left: 50%;
    background:#ccc;
}

Even more updated using jquery and always remain center when you resize the window too : http://jsfiddle.net/3aZZW/3/

Demo: http://jsfiddle.net/3aZZW/3/embedded/result/

Answer 2

There are different reasons why you should not use tables. Some which have already been discussed here. I understand that you are only using one row and you will hopefully try to keep your promise to not add any rows but if you come to break that promise, some of the reasons below will show a lot more significance, like the rendering speed and the screen reader issue. That's exactly why they call somethings standard and some not. Standards take everything and every situation into account.

Rendering speed issue:

One of the biggest drawbacks of tables is the way they are rendered by browsers. The inside of the table must be loaded before the position and size of the table can be exactly determined. This may cause problems if you are going to have a lot of information in the table.

Validness and standards:

Using tables for non-tabular data means you are writing invalid X/HTML. Which may be fine for some. But I don't recommend. See here

SEO:

I didn't know this before I did a search on some other less heard issues with using tables.

Search engines love valid code, so by not using tables it helps with Search Engine Optimization (SEO).

See here for more info on this

Problems for screen readers and Braille displays:

Tables can't be used easily in screen readers. Check this article.

If you must use a table for layout, remember that screen readers and Braille displays read tables row-by-row across the columns. The TAB order also goes through the table in this way. So make sure that your table structure makes sense when reading from left to right, row-by-row.

On the + side:

I hate to admit that if you honestly use just that one table with one row and one column and with a very small amount of data inside (which I would call a limitation) then the page would probably render faster than the time you use Javascript but the other issues remain.

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Answer 3

Tables are only meant to be used for tabular data - not for layout purposes.

Using tables for your problem provides a quick and easy solution for you but it doesn't mean it's the best, or correct method.

Just because something takes a little bit more thought and effort doesn't mean it should be avoided.

Use tables for this at your peril - your immortal soul may pay a heavy psychic toll at some future date for your actions today :p

Answer 4

According to StatCounter, as of November 2012, IE7 accounts for only 0.87% of the usage share of desktop browsers. It's not clear how accurate that measure is; some countries are probably disproportionately weighted and the sample-set almost certainly doesn't exactly match your user demographics, whatever they are. But, how much would you really lose by leaving IE7 behind? Might as well go with display: table;

On the other hand, it drives me nuts that display: table; is necessary. This is the closest I can get to a workable alternative:

HTML

<div id="pg-centerer">
    <div id="shifter">
        <div id="item">content</div>
    </div>
</div>

CSS

#pg-centerer {
    position: absolute;
    left: 50%;
    top: 50%;
}

#shifter {
    position: relative;
    height: 40px;           /** Must set the height here. **/
    left: -50%;
}

#item {
    position: relative;
    top: -50%;
}

So far, I haven't figured out how to avoid setting the height of the div#shifter element. Here's a working demo. I've tested this on Mac 10.8.1 FF 18, Safari 6.0, Chrome 25.0.1362.0 canary, and iOS Safari 6.0.1.

Answer 5

There is not much of a problem till you have small data inside table. Tables are somewhat heavy for browsers and with more data coming in, they make your web page response slower in comparison.

The example you have shown is only for an example but in real world you will have data inside it. If its going to be large try choosing a different method. may be the flexbox model or box model that is going to be supported in all modern browsers very soon. See an example here. http://www.kirupa.com/html5/centering_vertically_horizontally.htm

If the data inside is going to be small, feel free to user your method.

Answer 6

Directing my words to the geek inside who care not about standards, or multi-channeling content served... there is really just one technical problem with tables that I can think of, if you have large content inside that cell, the browser will wait for all content to load to be able to calculate the width and height of the cell before rendering... so if that content is really large and has large images, it will not render gradually... and making it a fixed table, well, the trick above won't work.

Answer 7

I depends on what you're trying to achieve. If it's just one page with one thing centered, then its great.

But I see you have set the table position: fixed. Which means it will scroll with you and go on top of content below. The other thing is that, if that table really fills up, you wont be able to see whats at the bottom of that table, since the position is set to fixed.

It's a great solution to center a small piece of text, image or information.

But its a bad thing to use within a page with a lot of other content or a lot of content within the table.

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Side note: Using javascript to achieve something simple like that, is stupid. It can be done without javascript using CSS only. What if you use javascript to center something, and a client without javascript visits? Lets not destroy the web by using javascript/jquery for all the simple things ;)