Is there a selector method that allows policing whether, eg. the HTML tag is a clean "<html>" with no attributes whatsoever?
I'm trying to create a Stylish override sheet for browser-generated image pages in Firefox, but I essentially have to apply it to all URIs since such pages are always still ostensibly from the images' own domains.
The easiest way seems to be testing whether the HTML and Body tags have zero attributes (plus only-child and class selection on the image tag) because the structure of most documents which haven't been generated by the browser won't start as simply as <html><body><img class="...
But all I can find is how to exclude a specific attribute, not all of them.
I've tried the following with no success:
[] {
color: blue;
}
[*] {
color: red;
}
<p>Clean element with no attributes</p>
<p class="has-class">Has class attribute</p>
<p id="has-id">Has ID attribute</p>
<p data-has-data-attribute="">Has data attribute</p>
The only remaining option I can come up with is just policing the standard attributes one would see ("class", "style", "name", "lang", etc.), but that's a lengthy and ever-changing list, notwithstanding the numerous non-standard ones.
A selector that matches a tag without attributes doesn't currently exist.
I read through the latest CSS selector reference and couldn't find a selector that does what you wish.
You can't use an asterisk in the attribute selector to select everything unfortunately. These two railroad diagrams represent what is allowed:
So your first two attempts are invalid, and the valid empty string seems to have no effect:
[] {
color: blue;
}
[*] {
color: red;
}
[""] { /* Seems to select nothing, rather than 'no attribute' */
color: magenta;
}
<p>Clean element with no attributes</p>
<p class="has-class">Has class attribute</p>
<p id="has-id">Has ID attribute</p>
<p data-has-data-attribute="">Has data attribute</p>
I can't come up with any possible hack that doesn't involve JavaScript. I will edit this answer if I figure out a solution.
Related
Trying to find a pseudo class that'll target a <div> like this:
<div class="nav-previous">
</div>
I've tried :blank and :empty but neither can detect it. Is it just not possible to do?
https://jsfiddle.net/q3o1y74k/3/
:empty alone is enough.
By the current Selectors Level 4 specification, :empty can match elements that only contain text nodes that only contain whitespace as well as completely empty ones. It’s just there aren’t many that support it as per the current specification.
The :empty pseudo-class represents an element that has no children except, optionally, document white space characters.
From the MDN:
Note: In Selectors Level 4, the :empty pseudo-class was changed to act like :-moz-only-whitespace, but no browser currently supports this yet.
The :-moz-only-whitespace CSS pseudo-class matches elements that only contain text nodes that only contain whitespace. (This includes elements with empty text nodes and elements with no child nodes.)
As the others mentioned, this isn't possible with CSS yet.
You can check to see if there's only whitespace with JavaScript however. Here's a simple JS only solution, "empty" divs that match are blue, while divs that have text are red. Updated to add an empty class to the empty divs, which would allow you to target them easily with the selector .empty in your CSS.
The JS only "empty" comparison would look like this:
if(element.innerHTML.replace(/^\s*/, "").replace(/\s*$/, "") == "")
And if you're using jQuery it would be a bit easier:
if( $.trim( $(element).text() ) == "" ){
var navs = document.querySelectorAll(".nav-previous");
for( i=0; i < navs.length; i++ ){
if(navs[i].innerHTML.replace(/^\s*/, "").replace(/\s*$/, "") == "") {
navs[i].style.background = 'blue';
navs[i].classList.add( 'empty' );
} else {
navs[i].style.background = 'red';
}
}
.nav-previous {
padding: 10px;
border: 1px solid #000;
}
.nav-previous.empty {
border: 5px solid green;
}
<div class="nav-previous">
</div>
<div class="nav-previous">Not Empty </div>
The problem with your approach is that your container is not actually empty.
The :empty pseudo-class represents an element that has no children at
all. In terms of the document tree, only element nodes and content
nodes (such as DOM text nodes, CDATA nodes, and entity references)
whose data has a non-zero length must be considered as affecting
emptiness;
As you have empty spaces this pseudo class will not do the trick.
The :blank pseudo class should be the right one, because this is its definition:
This blank pseudo-class matches elements that only contain content
which consists of whitespace but are not empty.
the problem is that this pseudo class isn't implemented by any browser yet as you can check in the link below. So you will need to wait until it get implemented to be able to use this selector.
This pretty much explains the behavior you are facing
https://css4-selectors.com/selector/css4/blank-pseudo-class/
The best approach here is just to be sure that your div will actually be empty, so your approach will work.
the best that you can do is to define an empty class like this:
.empty{
display:none;
}
and then add this JS code here, it will append the empty class to your blank items:
(function($){
$.isBlank = function(html, obj){
return $.trim(html) === "" || obj.length == 0;
};
$('div').each(function() {
if($.isBlank(
$(this).html(),
$(this).contents().filter(function() {
return (this.nodeType !== Node.COMMENT_NODE);
})
)) {
$(this).addClass('empty');
}
});
})(jQuery);
check it working here,
https://jsfiddle.net/29eup5uw/
You just can't without JavaScript/jQuery implementation.
:empty selector works with empty tags (so without even any space in them) or with self-closing tags like <input />.
Reference: https://www.w3schools.com/cssref/css_selectors.asp
If you want to use JavaScript implementation, I guess here you will find the answer: How do I check if an HTML element is empty using jQuery?
:empty indeed only works for totally empty elements. Whitespace content means it is not empty, a single space or linebreak is already enough. Only HTML comments are considered to be 'no content'.
For more info see here: https://css-tricks.com/almanac/selectors/e/empty/
The :blank selector is in the works, it will match whitespace, see here: https://css-tricks.com/almanac/selectors/b/blank/. But it seems to have no browser support yet.
Update:
See here for possible solutions to this involving jQuery.
I would like to select anchor tags only when they're completely by themselves, that way I can make those look like buttons, without causing anchors within sentences to look like buttons. I don't want to add an extra class because this is going within a CMS.
I originally was trying this:
article p a:first-child:last-child {
background-color: #b83634;
color: white;
text-transform: uppercase;
font-weight: bold;
padding: 4px 24px;
}
But it doesn't work because text content isn't considered as criteria for :first-child or :last-child.
I would like to match
<p><a href='#'>Link</a></p>
but not
<p><a href='#'>Link</a> text content</p>
or
<p>text content <a href='#'>Link</a></p>
Is this possible with CSS?
The simple answer is: no, you can't.
As explained here, here and here, there is no CSS selector that applies to the text nodes.
If you could use jQuery, take a look at the contains selector.
Unfortunately no, you can't.
You have to use JS by it self or any librady of it to interact with content of elements and found where is each element in the content.
If you wish me to update my answer with a JS example prease ask for it.
I don't think it's generally possible, but you can come close. Here are some helpful places to start:
The Only Child Selector which would allow you to select all a elements which have no siblings like so a:only-child {/* css */}. See more here. (Also see edit)
The Not Selector which would allow you to exclude some elements perhaps using something along the lines of :not(p) > a {/* css */} which should select all anchors not in a paragraph. See some helpful information here.
Combining selectors to be as specific as possible. You might want all anchors not in an h1 and all anchors not in a p.
Example:
The final product might look like this:
a:only-child, :not(p) > a {/* css */}
This should select all anchors that are only children and anchors that are not in a paragraph.
Final note:
You may want to consider making the buttons actual button or input tags to make your life easier. Getting the HTML right first usually makes the CSS simpler.
Edit: the only child ignores the text, so that's pretty much useless here. I guess it's less doable than I thought.
jQuery Code Example:
// this will select '<p><a></a></p>' or '<p><a></a>text</p>'
// but not '<p><a></a><a></a></p>'
$('p').has('a:only-child').each(function() {
const p = $(this); // jQuerify
let hasalsotext = false;
p.contents().each(function(){
if ((this.nodeType === 3) && (this.nodeValue.trim() !== "")) {
hasalsotext = true;
return false; // break
}
});
if (!hasalsotext) {
$('a', p).addClass('looks-like-a-button');
}
});
I am developing a website which relies on user input to create scripts
As a defense in depth solution I am adding a blacklist protection to omit all links with an external source. I tried the following code snippet but it doesn't work (my browser supports it because w3schools sample works on it) :
[href~=//]
{
display: none;
}
There's a subtle different in the selectors that you are using :
[attribute~="value"] - This checks for a specific word (i.e. wrapped in white-space or the exact string)
[attribute*="value"] - This checks if a given set of text is contained at all.
You'll see that the second approach works, whereas the first does not.
Additionally, you'll want to ensure that you have the specific element you are targeting and that you are wrapping your value within quotes, as seen below :
a[href*='//']{
display: none;
}
Example
a[href*='//'] {
display: none;
}
/* Added to demonstrate selector differences */
a[href~='//'] {
color: green;
display: block;
}
<h4>[href*="value"] Examples</h4>
<a href='http://www.google.com'>Hidden</a>
<a href='stackoverflow.com'>Shown</a>
<a href='Check // this out'>Green</a>
<h4>[href~="value"] Examples</h4>
<a href='a//'>Hidden (since not whole "word")</a>
<a href='//'>Shown (as exact)</a>
<a href='//a'>Hidden (since not whole "word")</a>
Try this:
a[href*="//"]{
display:none;
}
Select all a objects whose href contains '//'
working fiddle
I have some legacy CSS I wanted to clean up. Person who wrote it is not available for consultation. The following rule does not validate (CSS 2.1):
html[lang=en] q: before, : lang(en) q: before {
content: "“";
}
Would it be safe to assume that the author mean the following (this validates):
html[lang=en] q:before, q:lang(en):before {
content: "“";
}
Also, is the first selector different from the second one in any way? Is each specific to a certain browser?
Thanks.
This selector does not appear to work in Firefox:
: lang(en) q: before
It is probably supposed to be
:lang(en) q:before
Which is not the same as
q:lang(en):before
You can see this in action with the following test case:
:lang(en) q:before {
content: "a";
}
q:lang(en):before {
content: "b";
}
<div lang="en">
<q lang="zh">Hello zh</q> <q lang="en">Hello EN</q> <q>Hello Plain</q>
</div>
This gives
a"Hello zh" b"Hello EN" b"Hello Plain"
Basically the :lang(en) q:before rule says "Before any Q inside any element with English language", while q:lang(en):before says "before any Q that is in the English Language".
Also, the two selectors that are used (html[lang=en] q:before and :lang(en) q:before) are not exactly equivalent but will achieve the same effect most of the time if the browser in question understands one of the selectors. :lang(en) is a newer selector that identifies the language while html[lang=en] is an attribute selector that merely identifes some attribute called lang.
this is definately wrong :
before, : lang(en)
the , : can't be used like this, the comma indicates a new "rule", the colon a pseudp property (like in a:link).
P.S. do content and before work in IE?
In css examples, I've seen rules defined starting with a . and some starting with # - sometimes these are mixed in the same file. What is the difference between these rules:
h1 { font-size:18pt;}
.new-alerts { font-size:11pt; font-weight:bold;}
#old-alerts { position:relative; font-size:10pt; }
Are they referenced differently on the html page? Is it how the properties are inherited?
. refers to a class. <span class="one" /> could be selected with .one.
# refers to an ID. <span id="one" /> could be selected with #one.
You should be using classes when there could be more than one of a given element, and IDs when you know there will only be one. #navigation-bar would be using an ID because you will only have one navigation bar in your layout, but .navigation-link would be using a class name because you will have multiple navigation links. (It'd be better practice to use #navigation-bar a:link to get the navigation links, but you get my point.)
The dot . is a class selector, the hash/pound/octothorpe # selects by an ID:
<style>
.foo { ... }
#bar { ... }
</style>
...
<p class='foo'>Foo</p>
<p id='bar' class='baz'>Bar</p>
IDs have to be unique throughout a document, classes don't have to be. That's basically the primary difference. There are some things to note with regard to scripting but those are usually not of particular interest when styling.
Furthermore, an element may belong to multiple classes:
<p class="foo bar baz">
and as seen above, classes and IDs are not mutually exclusive.
. is a class and can be reused many times and for different elements
# is an ID and must be used only once on each page.
See Class vs ID