shared-session-storage.js

// This script must load first in all tabs!
// Transfers sessionStorage from one tab to another
var sendSessionStorage = function () {
    localStorage.setItem("sessionStorage", JSON.stringify(sessionStorage));
    localStorage.removeItem("sessionStorage");
}

var loadSessionStorage = function () {
    var data = JSON.parse(event.newValue);
    for (var key in data) {
        sessionStorage.setItem(key, data[key]);
    }
}

var sessionStorage_transfer = function (event) {
    console.log(`Storage event ocurred in '${event.storageArea}'`);
    if (!event) { event = window.event; } // ie suq
    if (!event.newValue) return;          // do nothing if no value to work with
    if (event.key === "getSessionStorage") {
        console.log("\tSending session storage");
        sendSessionStorage();
    } else if (event.key === "sessionStorage" && !sessionStorage.length) {
        console.log("\tLoading session storage");
        loadSessionStorage();
    } else if (event.key === "updateSessionStorage") {
        debugger;
        var key = event.newValue.split(":")[0];
        var value = event.newValue.replace(`/${key}:/`, "");
        sessionStorage.setItem(key, value);
    } else if (event.key === "deleteSessionStorageItem") {
        debugger;
        sessionStorage.removeItem(event.newValue);
    }
};

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


var triggerStorageSyncEvent = function () {
    localStorage.setItem("getSessionStorage", "foobar");
    localStorage.removeItem("getSessionStorage");
}

// Ask other tabs for session storage (this is ONLY to trigger event)
if (!sessionStorage.length) {
    triggerStorageSyncEvent();
};