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CSS Selectors

CSS Selectors
CSS Selectors

CSS Selectors: A CSS selector selects the HTML element(s) you need to style.

CSS selectors are used to select the content you need to style. Selectors are the part of CSS rule set. CSS selectors select HTML elements as per its id, class, type, attributes and so forth


In this tutorial, you will learn-

CSS Selectors

CSS selectors are used to “find” (or select) the HTML elements you need to style.

We can divide CSS selectors into five classifications:

• Simple selectors (select elements dependent on name, id, class)

• Combinator selectors (select elements dependent on a particular relationship between them)

• Pseudo-class selectors (select elements dependent on a specific state)

• Pseudo-elements selectors (select and style a part of an element)

• Attribute selectors (select elements dependent on an attribute or attribute value)

This page will clarify the most fundamental CSS selectors.


The CSS element Selector

The element selector selects HTML elements dependent on the element name.

Example

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

<!DOCTYPE html>
<html>
<head>
<style>
p {
  text-align: center;
  color: red;
} 
</style>
</head>
<body>

<p>Every paragraph will be affected by the style.</p>
<p id="para1">CSS Tutorial!</p>
<p>Learn CSS!</p>

</body>
</html>

The CSS id Selector

The id selector uses the id attribute of an HTML element to select a particular element.

The id of an element is unique inside a page, so the id selector is used to select one unique element!

To select an element with a particular 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″: 

<!DOCTYPE html>
<html>
<head>
<style>
#para1 {
  text-align: center;
  color: red;
}
</style>
</head>
<body>

<p id="para1">Hello World!</p>
<p>This paragraph is not affected by the style.</p>

</body>
</html>

Note: An id name cannot start with a number!


The CSS class Selector

The class selector selects HTML elements with a particular class attribute.

To select elements with a particular 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:

<!DOCTYPE html>
<html>
<head>
<style>
.center {
  text-align: center;
  color: red;
}
</style>
</head>
<body>

<h1 class="center">Red and center-aligned heading</h1>
<p class="center">Red and center-aligned paragraph.</p> 

</body>
</html>

You can likewise determine that only specific HTML elements ought to be influenced by a class.

Example

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

<!DOCTYPE html>
<html>
<head>
<style>
p.center {
  text-align: center;
  color: red;
}
</style>
</head>
<body>

<h1 class="center">This heading will not be affected</h1>
<p class="center">This paragraph will be red and center-aligned.</p> 

</body>
</html>

HTML elements can likewise refer to more than one class.

Example

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

<!DOCTYPE html>
<html>
<head>
<style>
p.center {
  text-align: center;
  color: red;
}

p.large {
  font-size: 300%;
}
</style>
</head>
<body>

<h1 class="center">This heading will not be affected</h1>
<p class="center">This paragraph will be red and center-aligned.</p>
<p class="center large">This paragraph will be red, center-aligned, and in a large font-size.</p> 

</body>
</html>

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:

<!DOCTYPE html>
<html>
<head>
<style>
* {
  text-align: center;
  color: blue;
}
</style>
</head>
<body>

<h1>Hello world!</h1>

<p>Every element on the page will be affected by the style.</p>
<p id="para1">CSS Tutorial!</p>
<p>Learn CSS!</p>

</body>
</html>

The CSS Grouping Selector

The grouping selector selects all the HTML elements with a similar style definitions.

Look at the accompanying CSS code (the h3, h4, and p elements have a similar 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:

<!DOCTYPE html>
<html>
<head>
<style>
h1, h2, p {
  text-align: center;
  color: red;
}
</style>
</head>
<body>

<h1>Hello World!</h1>
<h2>Smaller heading!</h2>
<p>This is a paragraph.</p>

</body>
</html>

All CSS Simple Selectors

SelectorExampleExample description
#id#firstnameSelects the element with id=”firstname”
.class.introSelects all elements with class=”intro”
element.classp.introSelects only <p> elements with class=”intro”
**Selects all elements
elementpSelects all <p> elements
element,element,..div, pSelects all <div> elements and all <p> elements

Thanks for reading! We hope you found this tutorial helpful and we would love to hear your feedback in the Comments section below. And show us what you’ve learned by sharing your projects with us.

salman khan

Written by worldofitech

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