phpjs/functions/math/cos.js

php.js offers community built php functions in javascript

function cos(arg) {
  //  discuss at: http://phpjs.org/functions/cos/
  // original by: Onno Marsman
  //   example 1: cos(8723321.4);
  //   returns 1: -0.18127180117605912

  return Math.cos(arg);
}