script.js

const passwordBox = document.getElementById('password');
const length = 14;
const upperCase = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
const lowerCase = 'abcdefghijklmnopqrstuvwxyz';
const number = '0123456789';
const symbols = '@#$%^&*_+~|/?-=';
const allChars = upperCase + lowerCase + number + symbols;

function createPassword() {
  let password = '';
  password += upperCase[Math.floor(Math.random()*upperCase.length)];   
  password += lowerCase[Math.floor(Math.random()*lowerCase.length)];   
  password += number[Math.floor(Math.random()*number.length)];   
  password += symbols[Math.floor(Math.random()*symbols.length)];   

  while(length>password.length){
    password += allChars[Math.floor(Math.random()*allChars.length)];  
  }
  passwordBox.value = password;
}

function copyPassword() {
  passwordBox.select();
  document.execCommand('copy');
}