The onfocusin event triggers when an element is to get focus. You can try to run the following code to learn how to implement onfocusin event in JavaScript −
Example
<!DOCTYPE html> <html> <body> <p>Write below:</p> <input type="text" onfocusin="newFunc(this)"> <script> function newFunc(x) { x.style.background = "blue"; } </script> </body> </html>