May I know if there is any difference between HTML block elements (Eg. <p>, <div>,...) and CSS property display: block?
Since from what I have read they are the same, but why we still need to use display: block for some block level element.
What you call "HTML block elements" are elements who have their display property set to block so there is no difference between a <div> and a <span> with display:block;.
This display property is set by the user agent stylesheet (i.e your browser). You can view these properties in chrome dev tool under "user agent stylesheet".
The only reason I see of using display:block; for a div element is :
your target adience is using some obscur user agent that don't follow web stadards (very unlikely)
you need to override a previous CSS declaration like display:none;
There is no difference between... because block elements already have default css property display: block.
But we use display: block to show them again, when we hide/remove them from page using display: none.
Related
This shows that "display" is initially "inline" for all elements:
https://www.w3.org/TR/css-display-3/#the-display-properties
However, this says "(and assuming the DIV and the P both have 'display: block')":
https://www.w3.org/TR/CSS2/visuren.html#block-level
I did see this question that shows that the browser sets the default display value.
Difference between HTML block elements and CSS display block property.
Q. How does this reconcile with the CSS Spec. statement that "display" is initially "inline" for all elements? Does the CSS specification statement about "initially inline" refer to the state before the browser sets display:block for block-level elements?
Does the CSS specification statement about "initially inline" refer to the state before the browser sets display:block for block-level elements?
It refers to the default value of a property if nothing is defined including any browser default style.
Each property has an initial value, defined in the property’s definition table. If the property is not an inherited property, and the cascade does not result in a value, then the specified value of the property is its initial value. ref
The fact that you can read "(and assuming the DIV and the P both have 'display: block')" confirms the logic because the Specification is not telling you that p and div should be or are block elements but let's assume they are block element for the sake of the explanation that comes next.
div and p are flow content (WhatWG) and thus presumably have "display: block" by default.
"Flow content" and "display: block" are not linked together. Some elements are flow content but they don't have "display: block" like a, span and many others.
The content models has nothing to do with the display value.
<div> defaults to block
<span> defaults to inline
Is there one that defaults to inline-block?
If not, what special tag name would be appropriate for me to apply 'inline-block' using CSS?
Or should I stick to using a class?
From what I can tell the <img> tag is the only inline-block by default. To be on the safe side I would recommend a class, you never know when changing all elements of a certain type will come back to bite you. Or, you could always make up your own tag and assign display:inline-block; to it. This way you aren't changing the default functionality of standard elements...
EDIT
It also appears that button, textarea, input, and select elements are also inline-block
Sources:
According to this img is inline-block http://dev.w3.org/html5/markup/img.html#img-display
And here claims that button, textarea, etc. are as well: http://www.w3.org/TR/CSS2/sample.html
EDIT #2
While the source above claims that img tags are inline-block it seems (thanks to Alohci) that they are just inline http://jsfiddle.net/AQ2yp/
The following were tested in Firefox:
button is inline-block: http://jsfiddle.net/GLS4P/
textarea is inline: http://jsfiddle.net/235vc/
input is inline: http://jsfiddle.net/RFKe8/
select is inline-block: http://jsfiddle.net/5B4Gs/
Is there one that defaults to inline-block?
Strictly speaking, no there isn't. The W3 HTML specifications do not ever specify default CSS property values for any elements. They do provide a "default style sheet" for HTML 4, but developers are only encouraged to use it - it is not a requirement or any sort of mandate. The HTML 5 specifications indicate "typical default display properties" but, again, those are not required (also keep in mind that HTML 5 is still a working draft anyways).
So that leaves all default values up to the browser and how the developers actually feel elements should be displayed to a user. No one can guarantee that a specific element will display as inline-block or any other way in someone's browser. You should always explicitly set that if you want it to happen. Don't rely on "defaults."
If not, what special tag name would be appropriate for me to apply 'inline-block' using CSS? Or should I stick to using a class?
This is up to you and how you are designing your pages. You should always use elements that are semantically appropriate to the content contained within them. If the element will always be used in a context which will require inline-block display, by all means set it to that in your style sheet. Otherwise, you will have to resort to classes or more specific selectors in order to make your elements display properly.
Here is a Fiddle that gets the default display value for a majority of HTML tags.
Fiddle
In chrome, the default inline-block elements are: "INPUT", "BUTTON", "TEXTAREA", "SELECT"
My solution to this is declaring what I call a slice.
CSS
sl {
display: inline-block;
}
Usage
<sl>inline block stuff</sl>
You can check my codepen with all HTML elements and their display property by default. Some tags are syntax-broken, but it does not matter for our purpose.
Currently, there are 5 elements with display: inline-block in FF :
<button>
<select>
<meter>
<progress>
<marquee>
And additional 2 (including 5 above) in Chrome:
textarea
input
In principle, it depends on the browser what the default value for the display property is for each element. Even HTML5 drafts do not prescribe what values must be used, though it presents “expected rendering” of elements in terms of CSS.
According the default style sheet for HTML in the CSS 2.1 specification, the elements that have display: inline-block by default are button, input, select, and textarea. Browsers use such settings, except that in Firefox, this only applies to button and select.
In the Rendering section of HTML5 CR, the meter and progress elements are additionally describes as having inline block as “expected rendering”, and browsers that have implemented these elements appear to behave that way. The keygen element is also described as being an inline block, but Firefox does not do that (it implemented keygen internally as select in the DOM); IE does not support keygen at all; Chrome implements it as suggested.
Since all of these elements have rather specialized meanings, functionality, and rendering idiosyncracies, none of them is adequate for general use as an element that is an inline block by default and may have various meanings. What you can use for such an element is normally span or div, depending on whether you prefer inline or block as the default rendering.
Now you can create a Custom Element (for example: <inline-block> or whatever) that will have its CSS property display set to inline-block by default.
customElements.define( 'inline-block', class extends HTMLElement {
constructor() {
super()
this.attachShadow( { mode: 'open' } )
.innerHTML = `<style> :host { display: inline-block } </style>
<slot></slot>`
}
} )
#hw { background-color: lightblue }
<inline-block id="hw">Hello World</inline-block>
button, textarea, input, and select default to inline-block.
In the event you would want to inline-block a div you'd give it a class name.
.inline-block {
display: inline-block
}
Then...
<div class="inline-block"></div>
CORRECTION
I was mistaken about img. It seems it defaults to inline and not inline-block
This isn't really a true answer to the question right now, but with enough support, it may someday be.
<seg> short for "segment". As in, segments of a line.
with the polyfill:
<style> seg { display: inline-block; } </style>
It really would be nice if there was an official one, but there is not, so here is the best (IMO) suggested name for such an element that I know of.
YES there is an element that defaults to inline.
The answer is the span element.
<span>
I am trying to understand the CSS specifications on http://www.dynamicdrive.com/style/csslibrary/item/matt_black_tabs/.
I tried to understand what difference and why put those properties just at the li and the a elements. What if the display was inline or block? I have tried to close some styles to see how it looks and I can't understand it.
Why is the display on the li and a elements set to inline and block? What would happen without those specifications?
The display property tells what style you want your object arranged. When you use block style it displays it like paragraphs and headers. Inline is default and has no line break before or after it. For more information on display go to
http://www.htmldog.com/guides/cssadvanced/display/
I have a situation where I would like an HTML img which has not yet loaded to have a pre-set height. The reason is that this height will be used in a calculation that may fire before the image is fully loaded and needs to remain accurate. I tried the following:
<div>hello<img src='http://example.com/invalid.gif' class="testimage"> there</div>
and put in some css
.testimage {
height: 200px;
width: 200px;
}
and at least in Firefox 5, the extra space is not rendered (and oddly, the broken image doesn't show either, just a blank space). That is, until I add display: inline-block. In at least some other browsers the default display of inline produces the desired result. Is this expected? If so, why?
Here's a jsFiddle as well: http://jsfiddle.net/uYXD4/
it says here that images are inline elements - http://htmlhelp.com/reference/html40/special/img.html
On the other hand take a look here - Is <img> element block level or inline level?
It looks like the <img> element is kind of both inline and block. No strict rules defining it, so probably the browser vendors make their own decisions about the defaults. So your best bet is to reset their assumptions to display: inline-block
Images are replaced elements:
An element whose content is outside the scope of the CSS formatting model, such as an image, embedded document, or applet. For example, the content of the HTML IMG element is often replaced by the image that its "src" attribute designates.
For replaced elements, display: inline-block is supposed to have the same exact same efffect as display: inline, which is the default.
So this may be a possible explanation for that strange behaviour in some browsers*:
They treat only completely loaded images as replaced elements, and otherwise treat them as non-replaced elements. That makes sense after all, and the standard does not explicitly disallow that. As a consequence, there's 3 possible scenarios:
replaced element, inline or inline-block doesn't matter, height property works
inline non-replaced element, height attribute has no effect
inline-block non-replaced element, height property works
Loaded images always qualify as 1., and broken/loading images may qualify as 1. or 2. (or 3. if you set display: inline-block explicitly)
*Not sure if that's how things actually work though.
Why not use something like
<img src="..." width=400 height=200>
I'm doing the exact same thing and it works quite well. Another option is...
$('.myimg').load( function() { /* ops */ } );
though I don't know if that waits to load the image in ALL browsers or not
Why is the default display style for image inline instead of inline-block?
Is there any difference between inline and inline-block for img elements, from what I can see it behaves exactly in the same way.
IMG is an Inline & Replaced element.
A replaced element is any element whose appearance and dimensions are
defined by an external resource.
As per W3C
The IMG element has no content; it is usually replaced inline by the
image designated by the src attribute, the exception being for left or
right-aligned images that are "floated" out of line.
Check this link for more http://reference.sitepoint.com/css/replacedelements
The default browser stylesheets were initially created using CSS1 for HTML3.2, so inline-block was not available or necessary. There's no difference between them for image elements.
References
CSS 1 Specification
HTML 3.2 Specification
The first part of your question is already answered, so I shall not repeat.
For the second part, some browsers like Firefox renders a no-image img tag as a span even when width and height attributes are specified in CSS.
You can try it out yourself with this HTML code:
<img alt='no image' src='about:blank'><br>
<img alt='no image' src='about:blank'id=iblock>
And corresponding CSS:
img {
height: 100px;
width: 100px;
background: cyan;
}
#iblock {
display: inline-block;
}
Or see the difference in rendering effect with this Demo on JsFiddle.
Inline-block allows you to manipulate the object's appearance with box-model styling (such as giving it dimensions), but allows you to keep the object aligned inline, like text.
Inline block is the same as inline, except for it allows you to adjust block properties such as padding and margin. By default, images are supposed to semantically flow with text like a diagram in a news article, that is why all the original attributes are to do with aligning the image with the text flow.
Inline-block is a newer CSS2 declaration, and not fully implemented in IE 6/7.
It's simply an inline element that supports dimension attributes: Embedded content - the img element.