phpjs/functions/strings/strtoupper.js

php.js offers community built php functions in javascript

function strtoupper(str) {
  // From: http://phpjs.org/functions
  // +   original by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
  // +   improved by: Onno Marsman
  // *     example 1: strtoupper('Kevin van Zonneveld');
  // *     returns 1: 'KEVIN VAN ZONNEVELD'
  return (str + '').toUpperCase();
}