sessionStorage and localStorage

window.storage_usage.js

//  Refer Link: https://developer.mozilla.org/en-US/docs/Web/API/Web_Storage_API/Using_the_Web_Storage_API
const STATE = `sessionStorage and localStorage are both window object's inner properties`;

function checkStorage(type) {
  let storage = window[type];
  let x = '__storage_test__';
  try {
    storage.setItem(x, x);
    storage.removeItem(x);
    return true;
  } catch(e) {
    return false;
    //  restrict demo is in the top link
  }
}

localStorage.setItem('foo', 'bar');
localStorage.getItem('foo');
localStorage.removeItem('foo');
localStorage.clear(); //  delete all

//  reaction when storageChange
window.addEventListener('storage', function() {
  //  codes
})

const STATE2 = `same as sessionStorage`;