Is it possible to add additional rules to a css block when using a "{ (properties of x) }" selector?
I looked at references but I can't find anything related to "properties of x". A link would be wonderful. I tried the following two combinations, but neither worked:
.dock li { (properties of grid_2; display:inline; background-color:#666; ) }
.dock li { display:inline; background-color:#666; (properties of grid_2) }
Many thanks!
EDIT
Apparently I misread an article and thought that such a syntax existed. I thought one could create a class and let it inherit the properties of another using such syntax, which is evidently not the case.
CSS does not have such a feature.
What you are describing is not possible. I think there are two other possibilities you could maybe use. The first is, that you need to know that several styles can be applied to an element at the same time. I'll give you an example:
li { font-size: 10pt; }
.dock li { color: #ff0000; }
All list items will be formatted with a font size of 10 points and only those within an element containing the dock class will be red.
My second suggestion is that you try applying two or more classes to your HTML element, for instance:
.grid li { font-size: 10pt; }
.dock li { color: #ff0000; }
Now put the grid and dock class into your HTML, and the elements will apply both style definitions:
<ul class="grid dock"> ...
Whatever you consider best for your project: remember that the properties defined in the second style overwrite the properties of the first one (if they do not define the same properties at all, there will be no confusion).
maybe your question is not too strange..
What I understand is that you want to do something like:
.a { prop1: val; prop2: val; }
.b { prop3: val; prop4: val; }
.c { .a; .b; prop5: val; prop6: val; }
You want the class .c to inherit all the properties and values of .a and .b
If this is ok, you can do that using LESS.
To use your LESS code in your sites you have different ways to do it.
First of all check the original site: LESS.org
If you are on Mac check this site: LESS APP + PLUGINS
If you are on PC the less.js plugin should be easier to implement LESS in your sites: less.js usage
Hope it helps.
Happy coding y'all! :)
Related
It sounds like this is something that sass/less/mixins/jquery are required for right now.
What I'm looking to do is something like this:
.myClass {
color: blue;
}
h1 {
class: myClass;
}
I'm curious why this was not done already, given that CSS seems to be about inheritance/aggregation if nothing else.
Does it not make sense for some reason?
Or maybe it's just too complex?
Thanks!
...I don't know if this is the first '#extend' proposal, but it comes out because of its popularity in sass, apparently: http://tabatkins.github.io/specs/css-extend-rule/
and there is an early discussion of the proposal in this list thread: https://lists.w3.org/Archives/Public/public-houdini/2015Jan/0005.html
Not sure if it is going to be a future CSS standard. But you can already do it with SASS and SCSS. Here is SCSS syntax:
.myClass {
color: blue;
}
h1 {
#extend .myClass;
...
}
Documentation: https://sass-lang.com/documentation/at-rules/extend
Well, in effect what you are trying to do is to make your CSS properties defined in the .myClass block, apply in your h1 block, (correct me if I'm wrong).
If that's what you meant, you can already do that by simply adding myClass to your h1 tag like <h1 class="myClass">Header</h1> and in your CSS you would do this:
.myClass {
color: blue;
}
// or
h1.myClass {
color: blue; // To only target h1 that have the 'myClass' class
}
Will future CSS standard allow applying classes to elements in a style declaration?
Well as you can see we can already do that with HTML, so I doubt it.
I'm looking into LESS because I definitely see some of their benefits. For instance colour declaration.
One thing I don't understand tho, and maybe I'm not getting the flow right is - why use the following LESS snippet
.radius {
-webkit-border-radius:5px;
-moz-border-radius:5px;
border-radius:5px;
}
.btn-red{
background-color:red;
.radius;
}
.btn-green{
background-color:green;
.radius;
}
...
When we can use the .radius class in the html file right away. I'm left with the impression that LESS will add a ton of duplicate code once it gets compiled.
I'm using the following, which makes more sense. Same with font-size, margins, etc... Aren't classes used in such cases?
<div class="btn-red radius">Cancel</div>
<div class="btn-green radius">Go</div>
The snippet above does not benefit from SASS/LESS capabilities that much. Lets have a closer look and check this SCSS snippet.
// Abstract placeholder.
%radius {
border-radius: 5px;
}
// Put your global styling here.
// I'm assuming that you can alter the markup and have button.btn.btn-green
.btn {
// Color modifier.
&-red {
#extend %radius;
background-color: red;
}
&-green {
#extend %radius;
background-color: green;
}
}
The CSS output will be:
.btn-red, .btn-green {
border-radius: 5px;
}
.btn-red {
background-color: red;
}
.btn-green {
background-color: green;
}
And then you have to pick up Autoprefixer and vendor-prefixes issue is solved once and for all.
Because now, you can just specify the class btn_red or btn_green and all the buttons will automatically have a radius.
Your HTML should contain only the semantics, and styling or classes referring to styling should not be part of it.
That applies to the other classes as well. If for instance, you would rename btn_red to btn_cancel, you have a meaningful classname that you can apply to any kind of cancel button. And in the CSS you can specify that a cancel button is red and a 'Go' button is green, and both have a radius, without needing to modify the HTML at all.
So, the ultimate goal is to have the HTML describe the structure and the CSS describe how that structure should look. And a CSS preprocessor is only their to make a bulky spaghetti-like CSS file more structured.
There are several benefits.
You can use more semantic class names. Rather than encoding style information directly in your class names, (btn-red, radius) you could use a single class that conveys the usage of the style, rather than its contents.
You can avoid repeating yourself.
#radius-size: 5px;
-webkit-border-radius:#radius-size;
-moz-border-radius:#radius-size;
border-radius:#radius-size;
You can parameterize it so that you'd be able to use different radiuses (radii?) in different contexts.
.radius(#radius-size) { ... }
Because there are cases that developer has-no-access or don't-want to change the markup. and the only solution is to include all props from a predefined class.
for example:
you have bootstrap loaded (then you already have .has-success and .has-error classes) and if you want to use HTML5's native form validation using input's :valid and :invalid states, you have to use JavaScript to add/remove success/error classes based on input's states. but with this feature of LESS you can include all props of success/error class inside input's states. the code for this example could be something like this:
#myinput {
&:valid { .has-success; }
&:invalid { .has-error; }
}
I have a very wierd question, I dont know wether if its possible in css or not
Suppose I have say 3 different css classes as shown below, as you can see I have a common property of all these classes, I want to declare this color somewhere else and pass a reference to it here, so if next time I want to change the color I can simply change at one place rather than changing in all the 5 classes.
I know that you can use body{}, or a wrapper for this but that would affect the colors of the entire site right ? Is there a way to do this ?
Is this even possible ?
.abc {
color:red;
}
.abc2 {
color:red;
}
.abc3 {
color:red;
}
.abc4 {
color:red;
}
.abc5 {
color:red;
}
The bad news: you can't do it in CSS.
The good news: you can write in a meta-CSS language like LESS, which then processes a LESS file to pure CSS. This is called a "mixin".
In LESS:
#errorColor: red;
.error-color {
color: #errorColor;
}
#error-1 {
.error-color;
}
.all-errors {
.error-color;
}
More info: http://lesscss.org/#-mixins
if you want to declare all of them at a time, you can use:
.abc, .abc2, .abc3, .abc4, .abc5 {
color:red;
}
Or you can declare an additional class & add to all the .abc, .abc2.... & make its color:red;.
This can not be done with CSS, but that is still a very popular thing to do by using a CSS preprocessor such as LESS, SASS, SCSS, or Stylus.
A preprocessor will let you define a variable (say $red = #F00). It will replace the variable in your CSS document with the variable value for you, allowing you to write very DRY and module CSS.
This functionality is referred to as "CSS variables", which is part of the future spec, but not yet implemented on any browsers.
For now, the best way to do this in pure CSS is to declare an additional class for the desired "global", and then add that class to all relevant items.
.abc_global { color: red; }
.abc1 { /* additional styling */ }
.abc2 { /* additional styling */ }
<div class="abc1 abc_global"></div>
<div class="abc2 abc_global"></div>
With LESS
You are able to define that red color once:
.myRedColor {
color:red;
}
Now you can call that red on any CSS styles. Even NESTED styles! It's a wicked tool!
.abc1 {
.myRedColor;
}
.abc2 {
.myRedColor;
}
.abc3 {
.myRedColor;
}
.abc4 {
.myRedColor;
}
NESTED EXAMPLE:
.abc {
.itsEasyAsOneTwoThree{
.myRedColor;
}
}
Now all of our "itsEasyAsOneTwoThree" classes that are properly nested inside of an "abc" class will be assigned the red style. No more remembering those long #867530 color codes :) How cool is that?!
You can also use PostCSS with the plugin postcss-preset-env and support custom properties/variables, then use the :root selector to add global css variables.
:root {
--color-gray: #333333;
--color-white: #ffffff;
--color-black: #000000;
}
This question already has answers here:
Closed 11 years ago.
Possible Duplicate:
Should css class names like 'floatleft' that directly describe the attached style be avoided?
I was wondering what the best practices were for the naming and usage of CSS classes.
For instance, in a scenario where you want to center the text of both the button text and the header text, is it better to repeat this style in both classes like
.button-text {
text-align: center;
/*some properties*/
}
.header-text {
text-align: center;
/*other properties*/
}
Or is it better practice to move that style out into a separate class like
.center {
text-align: center;
}
.button-text {
/*some properties*/
}
.header-text {
/*other properties*/
}
and have the class of "center" applied to elements that have the classes of "button-text" and "header-text".
What it comes down to, is, should CSS class names represent what an element is "button-text" or "state, what an element looks like "center"?
Thanks!
A CSS class should represent what you use the element for, not what the element looks like.
Consider that you have headers that are red and bold, and change the design to large blue letters instead. If you named your classes after the look of the headers, you end up with:
.RedBold {
color: blue;
font-size: 200%;
}
Having a class named center is definitely the wrong approach - this class name already implies the presentation, that's not the point of defining presentation in a separate file. A better way to avoid code duplication would be:
.button-text, .header-text {
text-align: center;
}
.button-text {
/*some properties*/
}
.header-text {
/*other properties*/
}
Another option is specifying multiple classes, e.g. class="button text" instead of class="button-text". This gives you:
.text {
text-align: center;
}
.button.text {
/*some properties*/
}
.header.text {
/*other properties*/
}
Unfortunately, this approach has to be ruled out if you need to support MSIE 6.0, all other browsers (including newer MSIE versions) deal with multiple classes correctly. As other people already noted which solution you choose is mainly a question of maintenance - choose the one that will be easier to change and adapt to new requirements.
Maintainability is king. Whatever you find most easy to maintain - in my opinion, this is your second example.
It depends how much you will center text, the issue with the second point is that you could then end up with a long list of classes added to each element in your HTML which isn't so clean.
If these happen in, for example, a p tag a lot, then you'd possibly be better off putting one class in the parent so the children can inherit it.
i tend to group items together example like
.button-text, .header-text{
text-align:center
}
then if they need something unique add that to another
ie
.button-text{
font-size:22px;
}
.header-text{
font-size:44px;
}
class name's should be usefull but its not a biggie, just ensure they are unique. Often i name things based on their hierarchy within a page or section, as to prevent any accidental duplication.
I have a css class like:
.foo {
background-color: red;
}
then I have a class specified for a list:
.list1 li {
background-color: tan;
}
is it possible to set one style class to just point to another? Something like:
.list1 li {
.foo;
}
not sure how to articulate that - I just want the .list li style to be whatever I define for the .foo class.
You can use selector grouping:
.foo, .list1 li {
background-color: red;
}
No. The best you can do with "native CSS" is to use a multiple selector:
.foo, .list1 li {
...
}
Otherwise there are preprocessors that can help with this such as SASS.
Not with any syntax like that (and don't confuse a "class" (an HTML term) with a "class selector" or a "rule-set").
Your options are multiple classes, grouping selectors or preprocessing.
You might want to look into a CSS preprocessor such as SASS or LESS. You can define variables that can be used throughout your code. It greatly speeds up your coding when you're familiar with it.
http://sass-lang.com/
http://lesscss.org/
Using SASS:
$darkred : #841c14;
.box {
background: $darkred;
}
No you can't but you override it using naming differnt classes for example
.foo {
background-color: red;
}
.list1 li {
background-color: tan;
}
class ="list1 foo"
Inheritance is, as far as I know, not supported in CSS (2.1 at least)
Afaik, this isn't possible (yet) I hope it will be in the future. I always just copy+paste whatever I want to be the same into the desired selector or put the selector names one after another:
.foo,
.li,
.whatever
{styles}
Maybe someone else has another suggestion.
The above solutions aren't available if you don't have control over how 'foo' was defined.
So, if a JQuery solution is acceptable, just apply the original class to all instances of the new class/context. In this case:
$('.list li').addClass('foo')
to help clarify what is meant by overriding, if you want .list1 li to carry all the styles of foo, but just want to change it's color to tan, i would do this:
<span class = "foo">
<span class = "list1"><!--or whatever name you have for your new style-->
TEXT WITH INHERITED STYLE GOES HERE
</span>
</span>
I've a litte expand #Frank Carnovale solution (without css changing). After page loading:
$(function () {
$('.list li').removeClass('old1 old2 ...')
$('.list li').toggleClass('foo1 foo2 ...')
}
See also Does addClass in JQuery override any existing css class based styles?