I don't know well about css rules.
I've multiple classes with same property like "width".
When setting these classes to the Html tag,
whose width property is set to that tag?
For example.
.main{
width:600px;
border:1px solid #000;
}
.rule1{
width:400px;
min-height:10px;
}
.rule2{
width:300px;
background:#aaa;
}
<div class="main rule1 rule2">
Which rule's width property is set?
</div>
.rule2{
width:300px;
background:#aaa;
}
This one defines the width for the tag since it comes at the end. When you are having multiple classes for a tag, and a common style for them all then it is always the last rule which will overwrite all the previous rules.
CSS stands for Cascading Style Sheets, which means that all the rules defined for an element apply, and if there are several identical properties the last defined wins.
So, your min-height from .rule1 is applied, as well as background from the second rule is applied. However, when it comes to width (which both rules have), the last one defined is applied: width:300px.
Try putting .rule2 before .rule1 in your CSS file to see what it does!
The last rule wins when setting the multiple rules.
But if there is inline "style" , "style" wins.
A selector's specificity is calculated as follows:
count 1 if the declaration is from is a 'style' attribute rather than a rule with a selector, 0 otherwise (= a) (In HTML, values of an element's "style" attribute are style sheet rules. These rules have no selectors, so a=1, b=0, c=0, and d=0.)
count the number of ID attributes in the selector (= b)
count the number of other attributes and pseudo-classes in the selector (= c)
count the number of element names and pseudo-elements in the selector (= d)
The specificity is based only on the form of the selector. In particular, a selector of the form "[id=p33]" is counted as an attribute selector (a=0, b=0, c=1, d=0), even if the id attribute is defined as an "ID" in the source document's DTD.
Concatenating the four numbers a-b-c-d (in a number system with a large base) gives the specificity.
If the specificities are equal, then CSS 2.1 Section 6.4.1 comes into play:
Finally, sort by order specified: if two declarations have the same weight, origin and specificity, the latter specified wins. Declarations in imported style sheets are considered to be before any declarations in the style sheet itself.
Note that this is talking about when the style is defined, not when it is used. If classes .a and .b have equal specificity, whichever is defined last in the stylesheet(s) wins. ... and ... will be styled identically, based on the definition order of .a and .b.
you can overwrite the default behavior by adding
.rule1 {
width:400px !important;
min-height:10px;
}
This will make sure that this rule's width is used.
Simple, later one will overwrite the previous one for the same attribute like width or background color.
Note in main you have a border, and never been overwritten by rule1 and rule2 so it keeps the 5px solid red border.
Note that width:200px; is applied since it is the last one define width, so it overwrite previous (unless you use !important in previous one, even with !important, later one will overwrite previous !important)
I think you get the idea now!
Just define them in one css rule:
.main{
width:200px;
background: yellow;
min-height:10px;
border:5px solid red;
}
.main{
width:1000px;
border:5px solid red;
background: red;
}
.rule1{
width:2000px;
min-height:10px;
background: green;
}
.rule2{
width:200px;
background: yellow;
}
<div class="main rule1 rule2">
Which rule's width property is set?
</div>
.rule2{width:300px; background:#aaa;}
This is last css rule its override all css class rule, finally width:300px is compile...
Related
I have a situation in which I load a style with a selector that should be prioritized over another.
The situation looks like the one in this fiddle, in which a specific id selector is not being prioritized over another one that uses a class that is under a specific id.
--HTML
<div id="cont">
<p class="hello" id="hello">I wish I was blue</p>
</div>
--CSS
#hello {
color:blue;
}
#cont .hello {
color:red;
}
Result is red text
I'm pretty sure this could be possible without using !important - which I really would like to avoid since this will be maintained by designers with no css skills for A/B testing. I want to make a selector for them that they will only edit it's properties.
Edit: To be clear, the #hello selector is injected to the page and I want to change it to one that actually works, but I don't want to change the other selector for that purpose. Of course if I have no choice I will, but it seems reasonable to be that this css is valid as it is and overriding that selector should be possible without modifying it.
Simply use the :not selector to exclude the #hello element.
Change the first to:
#cont .hello:not(#hello) {
color:red;
}
Demo Fiddle
More on :not from MDN
The negation CSS pseudo-class, :not(X), is a functional notation
taking a simple selector X as an argument. It matches an element that
is not represented by the argument. X must not contain another
negation selector, or any pseudo-elements.
Alternatively- per the comments below, you can increase the specificity of the second selector whilst providing variations for various contexts:
#hello, #cont #hello, #hello.hello {
color:blue;
}
Demo Fiddle
I suggest you to add another id selector to the first set of CSS rules.
#cont #hello {
color:blue;
}
#cont .hello {
color:red;
}
DEMO http://jsfiddle.net/a_incarnati/53q74jah/
In this case the color was overridden in red because you were using just one id selector #hello and that it's less specific than a selector with 2 ids combined or one id and one class combined, like you have done:
#cont .hello {
color:blue;
}
One of the things to take into account when writing CSS code, it’s the concept of CSS specificity. Understanding well this concept will avoid you to have to use !important;
As Mozilla Developer Network defines it, specificity is nonetheless:
Specificity is the means by which a browser decides which property
values are the most relevant to an element and gets to be applied.
Specificity is only based on the matching rules which are composed of
selectors of different sorts.
The following list of selectors is by increasing specificity:
Universal selectors
Type selectors
Class selectors
Attributes selectors
Pseudo-classes
ID selectors
Inline style
You can measure specificity counting how many selectors are present in a CSS statement.
CSS Specificity can be represented by 4 columns of priority:
inline=1|0|0|0
id=0|1|0|0
class=0|0|1|0
element=0|0|0|1
Left to right, the highest number takes priority.
You don't need two different selectors. You can keep one:
.hello {
color:red;
}
#cont .hello {
color:blue;
}
http://jsfiddle.net/vkftfj2n/4/
Consider the following HTML markup:
<input id="foo" class="bar" name="baz">
Are the following selectors equal (or even valid):
CSS
input#foo.bar[name=baz] { }
input.bar#foo[name=baz] { }
input[name=baz].bar#foo { }
/* etc */
And is it possible to move the element name to, say, end?
Edit: I know what specificity is, I want to know in which order the tag, id, class and attributes need to be specified.
They are all valid, as they comply with the syntax of sequence of simple selectors. They are equivalent, since their meaning, including specificity, are defined in a manner that does not depend on the order of the components.
It is not possible to move the element name (type selector) to the end, for purely syntactic reasons. The spec says that a simple selector “always begins with a type selector or a universal selector. No other type selector or universal selector is allowed in the sequence”. This is to be interpreted so that the type selector, if present, must appear first. This is natural since there would be no way to distinguish it from e.g. a preceding class selector (a space could not be used since it has a quite special meaning in CSS selector syntax: .bar input is a valid selector and means something quite different from input.bar).
Please refer the answer of #Jukka as OP seemed to have changed the meaning of the question by minor edit, but if anyone's interested in specificity question before edit, than please read ahead.
First of all, neither of the selectors make sense, to be true, they are over specific.
Your selector holds an id which will be unique, so defining class as well as attr=val is not required
(If you are not using the same id for other element in some OTHER document..)
If for some case, you need them, say to override, like... (makes sense)
input#foo.bar[name=baz] {
/* More specificity overrides the selector below */
}
input[name=baz] {
/* Styles here */
}
Are the following selectors equal - YES, they are equal as far as the specficity goes, they all return a score of 121
Credits
(or even valid) - Completely Valid
Does order of tag(Not relevant), id, class - NO, whatever the order of attributes are, it doesn't matter.
BUT
The order of your CSS declaration block in the stylesheet matters, the last selector will override common properties as all the three selectors have equal specificity.
Demo (All three will render green text, regardless of the order of their attributes, but if you shuffle the CSS selectors block, the last one will override the common properties of previous two selectors - unless you define !important in one of the selector properties)
And is it possible to move the element name(Attribute) to, say, end? - YES
Pros & Cons —
All the selectors are overspecific
Bad as far as performance goes
Using attr=val selector, you are assuming that the value of the name attribute won't change, if it does, you will have to change your selectors as well.
P.S : Have an habit of quoting the attribute values.
Those are all legal:
<input type-"text" id="foo" class="bar" name="baz">
input#foo.bar[name=baz] { border:1px solid blue; }
input.bar#foo[name=baz] { border:1px solid red; }
input[name=baz].bar#foo { border:1px solid green; }
http://jsfiddle.net/hGj5B/
Remove the various style blocks and note that each selector will select the textbox.
By "equal", if you are asking is they have equivalent specificity, then the answer is yes given each selector has the same amount of elements, classes, attribute selectors, and ids. Since they are all equal, the order of the blocks in your stylesheet will serve to determine which conflicting styles will win out.
You cannot move the element to the end, as the other segments of the selector describe it by coming after.
Yes all of them are legal , But while execution the Later one Will over ride the Earlier Declarations,but some exceptions are there
check the Flow exceptions Here
input[name=baz].bar#foo { border:1px solid green; }
input.bar#foo[name=baz] { border:1px solid red; }
input#foo.bar[name=baz] { border:1px solid blue; }
input { border:1px solid #000000; }
http://jsfiddle.net/hGj5B/
for More Details Refer this Question..
The sequence of execution of CSS
I have the following css (in this order):
textarea, input[type="text"], select {
border: 1px solid #B5B8C8;
}
.ui-state-error, .ui-widget-content .ui-state-error, .ui-widget-header .ui-state-error {
border: 1px solid #CD0A0A;
}
and i have a text box that looks like this:
<input type="text" name="Applications" value="" id="Applications" class="fullRowTextBox ac_input ui-state-error" autocomplete="off">
and it seems to be using this color: #B5B8C8 instead of #CD0A0A color.
I thought the CSS below would trump the css above.
Any reasons why this textbox is not getting the #CD0A0A border color?
Its a matter of specificity as Quentin pointed out.
Think of specificity as four numbers beginning with (0,0,0,0):
!important rules always take precedence, only another !important
rule can override a previous one (its an accessibility feature of
CSS, designed to override the UA stylesheet)
The universal selector (*) has a specificity of 0 - Combinators like +
and ~ also have no specificity
Inline styles have the highest specificity (other than !important)
and count as the first number (1,0,0,0).
ID's (#test) count as the second number in the above set (0,1,0,0)
Classes, pseudo-classes and attribute selectors are the third number
(0,0,1,0)
Type selectors and psuedo-elements (p & ::after) take place of the
fourth number, and are the least specific
Remember that if two rules have the same specificity and specify the same property the latter in the stylesheet will win.
So in your example input[type="text"] has one type selector and one attribute selector which means its equal to (0,0,1,1) versus the second selector which is only specifying one class (which is equal to an attribute selector in specificity terms), which is == to (0,0,1,0).
To override the previous selector, you can include a type selector, such as:
input.ui-state-error {
border: 1px solid #CD0A0A;
}
Despite the two selectors having the same specificity, the second will take precedence due to the nature of the cascade.
A type selector + an attribute selector is more specific than a class selector so it is applied later in the cascade.
You can try input.ac_input ui-state-error { border: 1px solid #B5B8C8; }
Try add style to
#Applications.ui-state-error
Let's say I have the following HTML:
<span id="id1" class="class1 class2">This is a test</span>
and if #id1, .class1 and .class2 all have different sets of mutually exclusive CSS rules, which one wins? I have been testing an example and in one case it's choosing (I think) the one that is listed at the bottom of the CSS file, but in another case it seems non-deterministic.
Is there a specific rule in this case?
The basic principle of cascading in CSS is that you have one element, and one or more CSS rules that apply to the same element (because the element matches their selectors). In this process, all applicable styles are computed, with any conflicts resolved (or cascaded), and then, well, applied.
If the rules and their declarations are mutually exclusive, then none of them "wins" over any of the others per se, since there's no conflict to resolve and therefore nothing to override. For example, if you have these rules:
#id1 {
color: red;
}
.class1 {
border-width: 1px;
}
.class2 {
border-style: dashed;
}
Then your element will have red text and a dashed red border that's 1 pixel thick. There are no conflicts, so all of them will combine in effect. (Note that the border is red due to special behavior.)
jsFiddle preview
It's only when you have the same property declared in more than one rule that selector specificity and cascading become relevant, because then you'd need to override values for that same property. In that case, then as already mentioned IDs take precedence over classes and equally-specific rules are applied from the top down; read about selector specificity.
For example, if you have these rules:
#id1 {
color: red;
}
.class1 {
text-decoration: underline;
color: green;
}
.class2 {
text-decoration: none;
color: blue;
}
Then your element will have red text with no decoration, because
the color value in #id1 overrides that in both classes, and
the text-decoration value in .class2 overrides that in .class1.
jsFiddle preview
Remember that all this has to apply to the same element. If you have a parent that only has an ID, with a child that only has a class, then none of this will apply because you're dealing with entirely separate elements. What comes into play instead is inheritance, which is also covered in the document I link to above.
CSS reads up to down, so class2 will win!
More Info
http://css-tricks.com/specifics-on-css-specificity/
ID will take precedence over class.
If an element has same styles defined multiple times using ID, the latter will take precedence over the former except the case that you're using !important
The order of precedence with CSS is as follows:
1. !important
2. Inline styles which defined inside an HTML element
3. Internal styles which defined in the head section
4. External stylesheet which is a link to a sheet (<link rel="stylesheet" type="text/css" href="style.css" />)
5. Browser default
This is easy - the one that is closer and more refined win (just like life)
I.e.
Got a blank sheet then:
Start off with class - apply those (aka class1, class2)
But you know about that individual (id)
And then apply that..
So (if there is a "winner") the id wins
Unless the tag has style in its attributes - That would win
With this HTML code.
<div class="noote">
<p class="first admonition-title">Noote</p>
<p class="last">Let's noote.</p>
</div>
How can I set the color of Noote to be red with css?
I mean, how can I set something for (div class="noote") and (p class="first") under it with css?
Try this:
/*this will apply for the element with class first
inside the element with class noot */
.noote .first{
color:red;
}
/* If you wanted to apply a rule for both individually
you can do: */
.noote, .first{
border:1px solid red;
}
div.note{
...
}
Refers to the div element that has the class note.
p.first{
...
}
Refers to the p element that has the class first.
div.note p.first{
...
}
Refers to the p element inside note that has the class first.
In addition, if you want to set an element child without setting a class to it,
div.note p:first-child{
/* it refers to the first p that contains noote */
}
#amosrivera's got it.
It's worth nooting that descendant selectors require more CPU. I always use more specific rules where possible. So instead of
.noote .first{
backgorund:red;
}
You could say
.noote > .first{
backgorund:red;
}
A nominal difference in most cases, but still a good habit.
Really?
Descendant selectors are
inefficient... The less specific the
key, the greater the number of nodes
that need to be evaluated.
— Google "Let's make the web
faster" docs
And
Descendent selectors are a major slow
down to the Safari browser
— John Sykes, May 2008
Some performance tests show little impact, and most writers agree that it only makes a difference on very large documents.
But mainly, I'm just going with my programmer instinct — say what you mean, and no more.