phpjs/functions/math/deg2rad.js

php.js offers community built php functions in javascript

function deg2rad(angle) {
  // From: http://phpjs.org/functions
  // +   original by: Enrique Gonzalez
  // +     improved by: Thomas Grainger (http://graingert.co.uk)
  // *     example 1: deg2rad(45);
  // *     returns 1: 0.7853981633974483
  return angle * .017453292519943295; // (angle / 180) * Math.PI;
}