Editar o código:
ver o resultado »
Tente você mesmo - ©
w3ii.com
<!DOCTYPE html> <html> <body> <p>This example uses the HTML DOM to assign an "onfocus" event to an input element.</p> Enter your name: <input type="text" id="fname"> <script> document.getElementById("fname").onfocus = function() {myFunction()}; function myFunction() { document.getElementById("fname").style.backgroundColor = "red"; } </script> </body> </html>