With the transition effect, you can easily change the property values. You can also set a duration.
Let us try to change the height of an element:
Example
<!DOCTYPE html> <html> <head> <style> div { width: 150px; height: 150px; background: blue; transition: width 3s; } div:hover { height: 200px; } </style> </head> <body> <h1>Heading One</h1> <p>Hover over the below box to change its height.</p> <div></div> </body> </html>