According to the RFC4122  version 4 complaint. A GUID or UUID should be in below format

 xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx

// create uuidv4  using javascript 

function uuidv4() {
  return ([1e7]+-1e3+-4e3+-8e3+-1e11).replace(/[018]/g, c =>
    (c ^ crypto.getRandomValues(new Uint8Array(1))[0] & 15 >> c / 4).toString(16)
  );
}

To create or generate UUID or GUID in JavaScript use the following code with Math.Random() function

function uuid() {
  return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
    var r = Math.random() * 16 | 0, v = c == 'x' ? r : (r & 0x3 | 0x8);
    return v.toString(16);
  });
}