Generate 16 alphanumerics license JS

keygen.js

function generatelicense() {
  var result = '';
  var characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
  var charactersLength = characters.length;
  for (var i = 0; i < 16; i++) {
    result += characters.charAt(Math.floor(Math.random() * charactersLength));
    if (i === 3 || i === 7 || i === 11) {
      result += '-';
    }
  }
  return result;
}