Editar o código:
ver o resultado »
Tente você mesmo - ©
w3ii.com
<!DOCTYPE html> <html> <body> <p>Click the button to create an array, call the new ucase() method, and display the result.</p> <button onclick="myFunction()">Try it</button> <p id="demo"></p> <script> Array.prototype.myUcase = function() { var i; for (i = 0; i < this.length; i++) { this[i] = this[i].toUpperCase(); } }; function myFunction() { var fruits = ["Banana", "Orange", "Apple", "Mango"]; fruits.myUcase(); document.getElementById("demo").innerHTML = fruits; } </script> </body> </html>