phpjs/functions/math/tan.js

php.js offers community built php functions in javascript

function tan(arg) {
  //  discuss at: http://phpjs.org/functions/tan/
  // original by: Onno Marsman
  //   example 1: tan(8723321.4);
  //   returns 1: 5.4251848798448234

  return Math.tan(arg);
}