Say I have 3 divs side by side:
<body>
<div id="ok1">Content for id "ok1" Goes Here</div>
<div id="ok2">Content for id "ok2" Goes Here</div>
<div id="ok3">Content for id "ok3" Goes Here</div>
</body>
Then I apply a margin to one of them:
#ok1 {
display: inline-block;
margin-top: 20px;
}
#ok2 {
display: inline-block;
}
#ok3 {
display: inline-block;
}
Why is it that all three get a top margin?
This is because the two divs are inline with the first one. When you did display: inline-block; it moved the other two divs into a block with the first one.
If you take that out, it goes back to normal.
fiddle
thanks to #MosheKatz for the idea on inline-block
An inline formatting context is established between the elements, therefore the following applies:
9.4.2 Inline formatting contexts (w3.org)
In an inline formatting context, boxes are laid out horizontally, one after the other, beginning at the top of a containing block. Horizontal margins, borders, and padding are respected between these boxes. The boxes may be aligned vertically in different ways: their bottoms or tops may be aligned, or the baselines of text within them may be aligned. The rectangular area that contains the boxes that form a line is called a line box.
The default vertical-align value for inline elements is baseline.
You could change this value to something like top, thus changing the results (example)
div { vertical-align:top; }
Related
From the CSS Specification, I can gather that:
Since a float is not in the flow, non-positioned block boxes created before and after the float box flow vertically as if the float did not exist.
So it means that any non positioned, non floated adjacent elements around floated elements should act as if the floated element did not exist, right? And it works perfectly if the former element has no content. But once it has some text, the text appears below the floated element which it should not and should move under the floated element.
<head>
<style>
#left {
float: left;
width: 50%;
}
#right {
width: 40%;
}
div {
padding: 2px;
background-color: brown;
}
section {
margin-left: 5px;
padding: 2px;
background-color: dodgerblue;
}
</style>
</head>
<body>
<section id="left">
<h2>Content</h2>
<p>Good stuff</p>
</section>
<div id="right">
FOOBAR
</div>
</body>
Here the text "FOOBAR" appears below the floated section, and does not move under. Even if we remove the width of the FOOBAR div, it appears right of the floated element and not under it.
How do adjacent elements actually work around floated elements. I have tried a lot of videos but none seem to explain it.
YOUR ANSWER
A float element will never overlap inline elements , that is why FOOBAR is not displayed under the floated element. This is because float element was initially invented to give an effect of text wrapping around images and not overlapping them.
WHY AND HOW THINGS ARE DISPLAYED IN YOUR EXAMPLE ?
Every text is inside a line box in css. According to css specs a floated element may come between edge of a container and edge of a line box . In that case line box will accommodate as many words as it can inside it and give an effect of text wrapping the float element. In your case line box of FOOBAR can not accommodate FOOBAR inside it , besides floated element cause there is no space . So the line box breaks down below the floated element and hence FOOBAR is displayed inside its line box below the float. -
Usually people try to figure out how to vertically center stuff, I want to remove an instance of centered content and align and I'm stuck.
The content of the button (that is placed in a list in a table cell) is vertically centered by default. How can I remove this? How to align the contents of the <button> vertically to the top?
<table>
<tbody>
<td>
<ul>
<li>
<button>
<div>Content</div>
I have an example on jsFiddle.
button {
display: block;
position: relative;
background-color: pink;
width: 100%;
min-height: 200px;
}
<button>
<div>why?</div>
<div>are these centered vertically?</div>
<div>And how to remove it?</div>
</button>
Why the contents are vertically centered?
There's no specific reason. This is the way UAs handle the position of value/content of buttons (including <button>, <input type="button">)1.
How to remove vertical centering?
Well, there's a way to achieve that. First, a little background is needed.
But before that, you should note that <div> elements are supposed to be used where flow contents are expected. This means that they are NOT allowed to be placed inside <button> elements.
As per HTML5 spec (Which is at PR state right now):
Content model for element button:
Phrasing content, but there must be no interactive content descendant.
Therefore, a valid HTML could be like this:
<button>
why? <br>
are these centered vertically? <br>
And how to remove it?
</button>
Background
In an inline flow, inline-level elements (inline, inline-block) can be aligned vertically inside the parent by vertical-align property. Using that with a value other than baseline makes inline-level elements position somewhere other than the baseline of the parent (which is the default place).
The key point is that taller elements would affect the line box / baseline.
The Solution
First, in order to handle the position of the lines, we need to wrap them by a wrapper element like <span> as follows:
<button>
<span> <!-- Added wrapper -->
why? <br>
are these centered vertically? <br>
And how to remove it?
</span>
</button>
In cases that the parent - the <button> in this case - has an explicit height, by any chance if we could have a child element having the exact same height of the parent, we would be able to expand the height of the line box and surprisingly make our desired in-flow child - the nested <span> in this case - be aligned to the top vertically by vertical-align: top; declaration.
10.8 Line height calculations: 'vertical-align' property
This property affects the vertical positioning inside a line box of
the boxes generated by an inline-level element.
top
Align the top of the aligned subtree with the top of the line box.
EXAMPLE HERE
button { width: 100%; height: 200px; }
button > span {
display: inline-block;
vertical-align: top;
}
button:after {
content: "";
display: inline-block;
vertical-align: top;
height: 100%;
}
Last bot not least, if you'd like to use min-height rather than height for the button, you should use min-height: inherit; for the pseudo-element as well.
EXAMPLE HERE.
1 Chrome and Firefox also display the value of text inputs vertically at the middle while IE8 doesn't for instance.
Bootstrap adds padding above and below the button content (6 pixels). You can alter the padding amount with: button{padding:0px;} or button{padding-top:x; padding-bottom:y;} where x and y are whatever value you choose.
If you want to alter that button only give the button id="table" or something like that and then do: button#table{padding:0px;}
If you can avoid using vertical align you should as not all browsers support it.
I'm working through a CSS problem at http://www.codecademy.com/courses/web-beginner-en-jNuXw/0/1?curriculum_id=50579fb998b470000202dc8b (actually, just helping a friend learn HTML/CSS) and came across a curious issue. If you erase the content in any of the <p> tags within a <div>, the div shifts upward. For example, delete the word 'Mom' without deleting the <p>. As best as I can figure out, this is because the element is set to vertical-align: baseline and for some reason the baseline is changing. I just can't figure out exactly why it's changing or what is causing it to change.
To be clear, I'm not asking for help to get the div's to align. That's simply a matter of setting their vertical-align to 'top'. I'm just trying to understand how the document flow is calculated. The specific question is: why does the empty div shift upwards?
DEMO: jsFiddle
UPDATE: Here is a new jsFiddle - http://jsfiddle.net/tonicboy/2DtTw/3/ which removes a lot of rules to boil the problem down to a simplified use case. From this, we can see that when a <p> tag has text in it, the baseline of the parent <div> is set at the baseline of the text. When you remove the text, the baseline of the parent <div> is set to the bottom of the <div>. Why is that?
HTML:
<div class="friend" id="best_friend"><p>Arthur</p></div>
<div class="friend"><p>Batmanuel</p></div>
<div class="friend"><p>Captain Liberty</p></div>
<div class="friend"><p>The City</p></div>
<div class="friend"><p>Justice</p></div>
<div class="family"><p></p></div>
<div class="family"><p>Dad</p></div>
<div class="family"><p>Bro</p></div>
<div class="family"><p>Sis</p></div>
<div class="family"><p>Rex</p></div>
<div class="enemy"><p>Baron Violent</p></div>
<div class="enemy"><p>The Breadmaster</p></div>
<div class="enemy"><p>The Deadly Nose</p></div>
<div class="enemy"><p>Dinosaur Neil</p></div>
<div class="enemy" id="archnemesis"><p>Chairface</p></div>
CSS:
div {
position: relative;
display: inline-block;
height: 100px;
width: 100px;
border-radius: 100%;
border: 2px solid black;
margin-left: 5px;
margin-top: 5px;
text-align: center;
}
div p {
position: relative;
margin-top: 40px;
font-size: 12px;
}
.friend {
border: 2px dashed green;
}
.family {
border: 2px dashed blue;
}
.enemy {
border: 2px dashed red;
}
#best_friend {
border: 4px solid #00C957;
}
#archnemesis {
border: 4px solid #cc0000;
}
I think I've mostly figured out the reason, after digging through W3C specs. Here are three key items from the spec which may explain this behavior:
"Line boxes that contain no text, no preserved white space, no inline elements with non-zero margins, padding, or borders, and no other in-flow content (such as images, inline blocks or inline tables), and do not end with a preserved newline must be treated as zero-height line boxes for the purposes of determining the positions of any elements inside of them, and must be treated as not existing for any other purpose."
When you delete the text, the <p> element is no longer in-flow.
"The baseline of an 'inline-block' is the baseline of its last line box in the normal flow, unless it has either no in-flow line boxes or if its 'overflow' property has a computed value other than 'visible', in which case the baseline is the bottom margin edge."
Because there are no in-flow elements within the parent div, the baseline becomes the bottom margin.
Because the div's are set to display: inline-block, their default vertical alignment is 'baseline'
Because the other div's have in-flow elements (the <p> tags), their baseline is set to the text baseline.
And that is why the empty box's bottom margin aligns with the baseline of the <p> tags in the other div's.
The baseline of the element is shifting because the text inside the <p> determs the baseline height:
In an inline formatting context, boxes are laid out horizontally, one
after the other, beginning at the top of a containing block.
Horizontal margins, borders, and padding are respected between these
boxes. The boxes may be aligned vertically in different ways: their
bottoms or tops may be aligned, or the baselines of text within them
may be aligned.
source: http://www.w3.org/TR/CSS2/visuren.html#block-formatting
The height of each inline-level box in the line box is calculated. For
replaced elements, inline-block elements, and inline-table elements,
this is the height of their margin box; for inline boxes, this is
their 'line-height'.
source: http://www.w3.org/TR/CSS2/visudet.html#line-height
CSS assumes that every font has font metrics that specify a
characteristic height above the baseline and a depth below it. In this
section we use A to mean that height (for a given font at a given
size) and D the depth. We also define AD = A + D, the distance from
the top to the bottom.
source: http://www.w3.org/TR/CSS2/visudet.html#inline-box-height
So with this block being a inline-block and baseline is calculted based on the line-height which is calcuted by different font types. Because this <p> has no font/text the baseline will not be positioned.
place all the line-height: 0; and you will see that the one with no text/font doesn't react like the other does:
jsFiddle
So why are the other two elemets shifting that have text in them?
Well it's because the text excist of two lines of text. The margin of the text is bigger and uses more space, thus the baseline is pushed further
Why does the first element get pushed down when its child contains text? Why inline-block behaves like this?
And how can I allign divs side-by-side while allowing them to have children? I want the grey box to have a list of elements one on top of the other, while still having everything aligned like this(it works fine if boxes don't contain children):
The example is here: http://jsfiddle.net/uwRwM/1/
.box {
display: inline-block;
}
Easy fix. Add overflow:hidden.
This will force the element to contain the text.
.box {
overflow:hidden;
}
Working jsFiddle demo
Alternatively, you can set vertical-align:top.
.box {
vertical-align:top;
}
Working jsFiddle demo
The reason this is occurring, is because the default vertical alignment of an inline-block element is baseline. Thus the reason it was on the bottom.
I have two divs side by side. Both have the same size and display: inline-block. The only difference between the two is, the first one has some text and the second one is blank.
HTML:
<div>1</div>
<div></div>
CSS:
div {
display: inline-block;
border: 1px solid black;
width: 50px;
height: 50px;
}
The first div is lower than the second one.
I am aware of all the possible fixes, like adding some text or a to the second div. Adding vertical-align: top fixes this as well, of course.
What I want to know is, can someone explain, why a blank div has a different alignment than a div with some text in it?
JSFiddle
Inline-block boxes are, by default vertically aligned such that the baseline of the inline-block box aligns to the baseline of the line box in which it is rendered.
The baseline of an inline-block box with one line of text, is the baseline of that line. More generally, the baseline of an inline-block is the baseline of the last line of text that it contains. But that means that there is no baseline for an inline-block that contains no text.
In such a situation a fall back rule kicks in, and the bottom of the inline-block box is placed on the baseline of its line box.