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;
}

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″: 

Note: An id name cannot start with a number!

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

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;
}

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 center-aligned: 

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

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>

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;
}

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;
}

Simple selectors (select elements based on name, id, class)

The CSS element Selector

Simple selectors (select elements based on name, id, class)

The CSS element Selector

 

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