phpjs/functions/var/is_bool.js

php.js offers community built php functions in javascript

function is_bool(mixed_var) {
  // From: http://phpjs.org/functions
  // +   original by: Onno Marsman
  // +   improved by: CoursesWeb (http://www.coursesweb.net/)
  // *     example 1: is_bool(false);
  // *     returns 1: true
  // *     example 2: is_bool(0);
  // *     returns 2: false
  return (mixed_var === true || mixed_var === false); // Faster (in FF) than type checking
}