phpjs/functions/math/exp.js

php.js offers community built php functions in javascript

function exp(arg) {
  // From: http://phpjs.org/functions
  // +   original by: Onno Marsman
  // *     example 1: exp(0.3);
  // *     returns 1: 1.3498588075760032
  return Math.exp(arg);
}