Is there a way to determine if the browser window is a popup, or just a new window using target="_blank"?

Question

I'm maintaining a large application. In some areas, I have to check if the current window is a popup (opened using window.open()) or a new window (a new tab or window opened using target="_blank").

Here is an example of my problem:

    function CancelOutOfPage(cancelPath) {
        if (cancelPath != null && cancelPath != "" && window.opener == null) {
            location.href = cancelPath;
        } else if (referrerUrl != "" && window.opener == null) {
            // Just go back
            location.href = referrerUrl;
        } else {
            // It is a popup, close it.
            // MY PROBLEM IS HERE. IF THE WINDOW IS NOT A POPUP, BUT A AN OPENED PAGE
            // THE WHOLE WINDOW WILL CLOSE
            window.close();
        }
    }

Answer 1

You could just set a global variable when you open the popup, and then you know it's a popup if variable is a truthy value - if it's undefined it will be false:

In the calling page:

var popupWindow = window.open(page);
popupWindow.isPopup = true;

In the new window:

if (window.isPopup) { 
    window.close();
}

Update:

You could alternatively set the name of the window when you open with a popup. The window.open function takes a second parameter for the name, followed by optional window features.

In the calling page:

window.open("test.html", "Test Popup");

In the new window:

if (window.name.length) { 
    window.close();
}

Answer 2

You can give flag on window when you open it.

//in window from which you open new window
var w = window.open('');
w.someFlag = true;

//in opened window
console.log(window.someFlag);
if (window.someFlag){
    //do what you want
}

Answer 3

You can set the name of the new window by providing second parameter to window.open(), e.g.;

 var w = window.open("url", "__blank__")

at opened window,

 if (this.name === "__blank__") {/*do stuff*/} else {/*do other stuff*/}