How to detect/stop a user opening a new browser window?

Question

This is in context to an ASP.Net application. The application makes use of a specific data which is set for a page. After this data has been set all the operations from this page onwards use the set data.

The problem is that if the user opens another tab with a competing data it overwrites the older data for the same session and for the same user which invalidates the operations on the first tab.

I know the suggested way is to refactor the code to remove such coupling but that is not possible. Here's another thread that discussed this but didn't specify any solutions other than refactoring the code (http://stackoverflow.com/questions/632062/ways-to-detect-ctrl-n-or-when-a-user-opens-a-new-window)

So, how can I detect (and notify the user) or stop the user from opening another tab - through javascript/Jquery?

score 1 · Accepted Answer · answered Jan 27 '12 at 06:06

1

You could set a session variable isActive and set it to true, along with all the other session data when the user opens the application the first time. After this, if the user opens another tab, check to see if isActive is true. If it is, inform the user and don't set the data again.

In pseudo-code, your logic should flow like this

if (!isActive)
   //set session data
else
  //alert the user: You have another active session

This would be a better solution because there is no guarantee the user does not visit the page to set the session, then temporarily turn off Javascript to launch a new tab without you being notified.

answered Jan 27 '12 at 06:06

Ayush

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How to check if the user has opened another tab? – Sidharth Panwar Jan 27 '12 at 06:35
@SidharthPanwar: No idea. If you implement my solution, you don't need to know. – Ayush Jan 27 '12 at 06:38
Where would I keep the code that you've provided? On what event would it fire? – Sidharth Panwar Jan 27 '12 at 06:41
That would go into your server side code where you are setting the session data. Do note that the code I gave is pseudo code. You would have to change it to use it – Ayush Jan 27 '12 at 07:23

score 1 · Answer 2 · answered Jan 27 '12 at 06:21

You should realize that you cannot prevent multiple pages being open on the same site by the same user. A user can always do such an operation using multiple different browsers on the same computer or browsers on different computers. As such, what you really need to do is to design your application to either just handle this situation gracefully or detect such a conflict and decide what the safest action is to take when it occurs (chances are, at the server, you either ignore the data from all sessions but one or you somehow merge them all together). What the safe action is depends upon what the data is or how it was changed.

The most straightforward option is to coin a new server-based session for the user each time the user visits and, at the server, invalidate all previous sessions so any older session that tries to make any future updates to the server will be denied because of an invalid session. This prevents any sort of multi-session data conflict.

If you want to be able to inform the user when their session becomes invalid, you could do a slow poll of the server (say once every 20 mins) as long as the window is open and on your site to check the session validity such that you can inform the user when their session has expired.

How to detect/stop a user opening a new browser window?

2 Answers2