CSS Selectors

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CSS Selectors


A CSS selector selects the HTML element(s) you
want to style.

CSS Selectors
CSS selectors are used to "find" (or select) the HTML elements you
want to style.
We can divide CSS selectors into five categories:

Simple selectors (select elements based on name, id, class)
Combinator selectors (select
elements based on a specific relationship between them)
Pseudo-class selectors (select elements based on a certain state)
Pseudo-elements selectors (select
and style a part of an element)
Attribute selectors (select elements based on
an attribute or attribute value)

This page will explain the most basic CSS selectors.

The CSS element Selector
The element selector selects HTML elements based on the element name.

Example
Here, all <p> elements on the page will be
center-aligned, with a red text color: 

p
{
  text-align: center;
  color: red;
}

Try it Yourself »


The CSS id Selector
The id selector uses the id attribute of an HTML element to select a specific element.
The id of an element is unique within a page, so the id selector is
used to
select one unique element!
To select an element with a specific id, write a hash (#) character, followed by
the id of the element.

Example
The CSS rule below will be applied to the HTML element with id="para1": 

#para1
{
  text-align: center;
  color: red;
}

Try it Yourself »


Note: An id name cannot start with a number!








The CSS class Selector
The class selector selects HTML elements with a specific class attribute.
To select elements with a specific class, write a period (.) character, followed by the
class name.

Example
In this example all HTML elements with class="center" will be red and center-aligned: 

.center {  text-align: center;  color: red;}

Try it Yourself »

You can also specify that only specific HTML elements should be affected by a class.

Example
In this example only <p> elements with class="center" will be
red and center-aligned: 

p.center {  text-align: center;  color: red;}

Try it Yourself »

HTML elements
can also refer to more than one class.

Example
In this example the <p> element will be styled according to class="center"
and to class="large": 

<p class="center large">This paragraph refers to two classes.</p>
Try it Yourself »


Note: A class name cannot start with a number!


The CSS Universal Selector
The universal selector (*) selects all HTML
elements on the page.

Example
The CSS rule below will affect every HTML element on the page: 

*
{
  text-align: center;
  color: blue;
}

Try it Yourself »


The CSS Grouping Selector
The grouping selector selects all the HTML elements with the same style
definitions.
Look at the following CSS code (the h1, h2, and p elements have the same
style definitions):


h1
{
  text-align: center;  color: red;
}
h2
{
 
text-align: center;  color: red;}
p
{
  text-align: center;  color: red;
}
It will be better to group the selectors, to minimize the code.
To group selectors, separate each selector with a comma.

Example
In this example we have grouped the selectors from the code above: 

h1, h2, p
{
 
text-align: center;  color: red;}
Try it Yourself »



Test Yourself With Exercises

Exercise:
Set the text color of all <p> elements to red.


<style>
{
red;
}
</style>



Submit Answer »
Start the Exercise



All CSS Simple Selectors



Selector
Example
Example description


#id
#firstname
Selects the element with id="firstname"


.class
.intro
Selects all elements with class="intro"


element.class
p.intro
Selects only <p> elements with class="intro"


*
*
Selects all elements


element
p
Selects all <p> elements


element,element,..
div, p
Selects all <div> elements and all <p> elements















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Reference: https://www.w3schools.com/css/css_selectors.asp