Use the :active
CSS pseudo-class to style an element when the user presses down the left or primary mouse button.
Syntax
<element>:active {css-style}
Example 1
Changing the color of a link on mouse down:
a:active {color: red;}
Output
Click the following link and you will notice that on mouse down it will turn red. Test me
Example 2
Change the background color of a paragraph on click:
p:active {background-color: #eee;}
Output
Click on this paragraph and on mouse down its background color will change to light gray.
This is another line.