The closed property of the window object. The closed property tells you whether a window opened using window. open() is still open or not. You see, once a window is opened (using JavaScript), it’s closed property is immediately initialized, with a value of false.
How do you check if a window is already open in JavaScript?
The closed property of the window object. The closed property tells you whether a window opened using window. open() is still open or not. You see, once a window is opened (using JavaScript), it’s closed property is immediately initialized, with a value of false.