Html – Using “margin: 0 auto;” in Internet Explorer 8

csshtmlinternet-explorer-8

I'm in the process of doing some advance IE8 testing, and it seems that the old technique of using margin: 0 auto; doesn't work in all cases in IE8.

The following piece of HTML gives a centered button in FF3, Opera, Safari, Chrome, IE7, and IE8 compat, but NOT in IE8 standard:

<div style="height: 500px; width: 500px; background-color: Yellow;">
    <input type="submit" style="display: block; margin: 0 auto;" />
</div>

(As a work-around I can add an explicit width to the button).

So the question is: which browsers are correct? Or is this one of those cases where the behaviour is undefined?

(My thinking is that all the browsers are incorrect – shouldn't the button be 100% width if it's "display: block"?)

UPDATE: I'm being a dunce. Since input isn't a block-level element, I should have just contained it within a div with "text-align: center". Having said that, for curiosity's sake, I'd still like to know whether the button should or shouldn't be centered in the example above.

FOR THE BOUNTY: I know I'm doing odd things in the example, and as I point out in the update, I should have just aligned it center. For the bounty, I'd like references to the specs that answer:

If I set "display: block", should
the button be width 100%? Or is this
undefined?
Since the display is block, should
"margin: 0 auto;" center the button, or
not, or undefined?

Best Answer

Adding <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> solves the issue

Related Solutions

Html – Centering a div block without the width

Update 27 Feb 2015: My original answer keeps getting voted up, but now I normally use @bobince's approach instead.

.child { /* This is the item to center... */
  display: inline-block;
}
.parent { /* ...and this is its parent container. */
  text-align: center;
}

My original post for historical purposes:

You might want to try this approach.

<div class="product_container">
    <div class="outer-center">
        <div class="product inner-center">
        </div>
    </div>
    <div class="clear"/>
</div>

Here's the matching style:

.outer-center {
    float: right;
    right: 50%;
    position: relative;
}
.inner-center {
    float: right;
    right: -50%;
    position: relative;
}
.clear {
    clear: both;
}

The idea here is that you contain the content you want to center in two divs, an outer one and an inner one. You float both divs so that their widths automatically shrink to fit your content. Next, you relatively position the outer div with it's right edge in the center of the container. Lastly, you relatively position the inner div the opposite direction by half of its own width (actually the outer div's width, but they are the same). Ultimately that centers the content in whatever container it's in.

You may need that empty div at the end if you depend on your "product" content to size the height for the "product_container".

CSS 100% height with padding/margin

I learned how to do these sort of things reading "PRO HTML and CSS Design Patterns". The display:block is the default display value for the div, but I like to make it explicit. The container has to be the right type; position attribute is fixed, relative, or absolute.

.stretchedToMargin {
  display: block;
  position:absolute;
  height:auto;
  bottom:0;
  top:0;
  left:0;
  right:0;
  margin-top:20px;
  margin-bottom:20px;
  margin-right:80px;
  margin-left:80px;
  background-color: green;
}

<div class="stretchedToMargin">
  Hello, world
</div>

Fiddle by Nooshu's comment

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