Check if window was opened by script in JavaScript

Question

Is it possible to check if script opened a window with JavaScript?

I have User agreements and they are opened in a new window and when I try to close the window, this works:

<a href="JavaScript:window.close()" class="btn btn-default">Return</a>

But what I would like to accomplish is that if the user go directly to /agreeement and clicks close, that it redirects him to the homepage.

Using my current code in this case, I get a message:

Scripts may close only the windows that were opened by it.

And I understand why. That is why I would like to check whether the window was not opened from a script, and then redirect to index in that case.

`window.opener` returns `null` if there isn't an opener referrer — Marcos Pérez Gude, Jul 05 '16 at 07:51

score 8 · Accepted Answer · edited Feb 22 '20 at 16:13

8

window.opener will be null when the page is not opened by another window, and therefore can not be closed.

This code should should do the trick:

function goAway() {
    if(window.opener === null) {
        window.location.href = '<YOUR_DEFAULT_URL>';
    }
    else {
        window.close();
    }
}

You can find more details here

edited Feb 22 '20 at 16:13

Matthew Beck

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answered Jul 05 '16 at 07:50

Sufyan Jabr

791
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No it doesn't talk about != null ... it just explains what is window.opener... if you are a new developer reading that will not tell how to check if the page is opened by a script or a new window.... – Sufyan Jabr Jul 05 '16 at 07:55
@Marcos Pérez Gude Well i could delete this question then if thats a problem as i didnt knew how to approach this problem so i asked here – MePo Jul 05 '16 at 08:05
That's not a problem, we can mark as duplicated and the question will survive to the time, with the correct canonical reference. – Marcos Pérez Gude Jul 05 '16 at 08:11

score 2 · Answer 2 · answered Jul 05 '16 at 07:51

2

It's been a while since I've needed to do this, but you can get the window that opened the current window with window.opener

answered Jul 05 '16 at 07:51

conradj

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Didnt knew that. Thanks will try this – MePo Jul 05 '16 at 07:52

Check if window was opened by script in JavaScript

2 Answers2