Any way to identify browser tab in JavaScript?

Question

I need to be able to identify what tab I am in within the browser. Isn't there some bit of information I can get from the browser to identify the tab? I don't need to know anything about any other tabs, I just need an id for the tab I am in. It could be a random or sequenced number, or a date-time stamp, as long as it remains the same for the life of the tab.

I have a client side app that makes a BOSH over HTTP connection to a remote server, and if I open it in multiple tabs, each instance needs its own unique id or the app fails, so I just need some unique number that is associated with the tab for as long as that tab exists (i.e. something that survives page refresh as I navigate the site that provides this app). Seems like a no-brainer that should just be available in the browser, like window.tabId - that's all I need. I've got a serious development block because I cannot get past this simple, simple, simple solution that doesn't seem to exist. There must be a way (a cross-browser solution at that).

Any ideas?

Answer 1

SessionStorage is per tab/window, so you can define a random number in sessionStorage and get it at first if exists:

var tabID = sessionStorage.tabID ? sessionStorage.tabID : sessionStorage.tabID = Math.random();

UPDATE:
In some cases, you may have same sessionStorage in multiple tab (e.g. when you duplicate tab). In that case, following code may helps:

var tabID = sessionStorage.tabID && sessionStorage.closedLastTab !== '2' ? sessionStorage.tabID : sessionStorage.tabID = Math.random();
sessionStorage.closedLastTab = '2';
$(window).on('unload beforeunload', function() {
      sessionStorage.closedLastTab = '1';
});

Answer 2

You have to be using html5, but sessionStorage combined with a random guid would seem to be what you want.

Answer 3

You can not get tab id with javascript, how ever there is some solution that can help you with like using different session / cookies when user open new tab.

Some reference:

Get Browser Tab Index/Id

get urls of firefox tabs from firefox extension

How to differ sessions in browser-tabs?

Get a unique session in each browser tab

asp.net - session - multiple browser tabs - different sessions?

Answer 4

Since I don't have find no simple Javascript function as windows.currentTabIndex, I have written some lines of Javascript to fix an ID on each browser tabs when they are loaded.

function defineTabID()
    {
    var iPageTabID = sessionStorage.getItem("tabID");
      // if it is the first time that this page is loaded
    if (iPageTabID == null)
        {
        var iLocalTabID = localStorage.getItem("tabID");
          // if tabID is not yet defined in localStorage it is initialized to 1
          // else tabId counter is increment by 1
        var iPageTabID = (iLocalTabID == null) ? 1 : Number(iLocalTabID) + 1;
          // new computed value are saved in localStorage and in sessionStorage
        localStorage.setItem("tabID",iPageTabID);
        sessionStorage.setItem("tabID",iPageTabID);
        }
    }

This code save last tab's index in localStorage to update current value for new tabs and in sessionStorage to fix page's id !

I must call defineTabId() function in each pages of my application. Since I develop using a JSF templates, this is only defined in only one place :-)

Answer 5

One of the possible solutions is using "window.name" property, but I do not want to use it because somebody else can use it.

I found one more possible solution: using sessionStorage. It supported by FF3.5+, Chrome4+, Safari4+, Opera10.5+, and IE8+.

Answer 6

If there isn't any odds of a user opening 3 tabs within 2 milliseconds, could use a timestamp and store that into window.name and use that as the key in your lookup. The window.name value will stay with the tab until it is closed.

Timestamp

Answer 7

For anyone on here using React, I made a sneaky little hook:

import {useEffect, useMemo} from 'react'
import uniqid from 'uniqid'

export const TAB_ID_KEY = 'tabId'

export default () => {
  const id = useMemo(uniqid, [])

  useEffect(() => {
    if (typeof Storage !== 'undefined') {
      sessionStorage.setItem(TAB_ID_KEY, id)
    }
  }, [id])

  return id
}

Put this on your base App/Page component, or somewhere that you know will always be mounted.

It'll run the effect after mounting and set a unique id for the current tab in session storage, which is storage specific to the tab.

Duplicating the tab will get you a new id for the new tab, since the component will mount again and the effect will run, overwriting the previous tab's id

Answer 8

At least for chrome, there's an official answer since 2013: chrome.tabs API.