auto generate reference number is javascript code example

Example 1: javascript generate unique id

function uuidv4() {
  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);
  });
}

console.log(uuidv4());

Example 2: generate id js

Math.floor(Math.random() * 100)
//the bigger the number the bigger the output