Browser Sessionstorage. Share Between Tabs

browser sessionStorage. share between tabs?

You can use localStorage and its "storage" eventListener to transfer sessionStorage data from one tab to another.

This code would need to exist on ALL tabs. It should execute before your other scripts.

// transfers sessionStorage from one tab to another
var sessionStorage_transfer = function(event) {
  if(!event) { event = window.event; } // ie suq
  if(!event.newValue) return;          // do nothing if no value to work with
  if (event.key == 'getSessionStorage') {
    // another tab asked for the sessionStorage -> send it
    localStorage.setItem('sessionStorage', JSON.stringify(sessionStorage));
    // the other tab should now have it, so we're done with it.
    localStorage.removeItem('sessionStorage'); // <- could do short timeout as well.
  } else if (event.key == 'sessionStorage' && !sessionStorage.length) {
    // another tab sent data <- get it
    var data = JSON.parse(event.newValue);
    for (var key in data) {
      sessionStorage.setItem(key, data[key]);
    }
  }
};

// listen for changes to localStorage
if(window.addEventListener) {
  window.addEventListener("storage", sessionStorage_transfer, false);
} else {
  window.attachEvent("onstorage", sessionStorage_transfer);
};

// Ask other tabs for session storage (this is ONLY to trigger event)
if (!sessionStorage.length) {
  localStorage.setItem('getSessionStorage', 'foobar');
  localStorage.removeItem('getSessionStorage', 'foobar');
};

I tested this in chrome, ff, safari, ie 11, ie 10, ie9

This method "should work in IE8" but i could not test it as my IE was crashing every time i opened a tab.... any tab... on any website. (good ol IE) PS: you'll obviously need to include a JSON shim if you want IE8 support as well. :)

Credit goes to this full article:
http://blog.guya.net/2015/06/12/sharing-sessionstorage-between-tabs-for-secure-multi-tab-authentication/

Why is sessionStorage preserved across multiple tabs?

The session has to work that way to maintain state if you navigate to another link within the same application. If you want to open a tab without that session try using incognito mode. Incognito mode will open window with fresh session.

sessionStorage on new window isn't empty, when following a link with target="_blank"

Javascript sessionStorage Across tabs?

As far as html5 storage goes i would go for localStorage in your case.

See below for the differences.

Session Storage:

• Values persist only as long as the window or tab in which they
  
  stored.
• Values are only visible within the window or tab that
  created them.

Local Storage:

• Values persist window and browser lifetimes.
• Values are shared across every window or tab running at the same origin.

Read more here

Angular - sharing session between the tabs of the same browser

As Alex is pointing out in his comment, it's best to implement some form of authentication for this use case.

If you expect different users to use one machine and don't want their sessions to overlap, it's pretty much your only solution.

As you said yourself, sessionStorage is limited to a given tab while the next highest option would be localStorage (that one however remains even after closing the browser). Perhaps you could try to listen to a browser close event or remove the localStorage entry after a given time but that too is not even close to being reliable.

As for cookies, you'd be looking at the same situation as with localStorage.

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