Unbinding all keydown functions.

[codesignist]

In the close function, this code unbinds all keydown events:
$(document).off('keydown');

Need to describe a keyDown function:

keyDownEvent: function (e) {
    // Close lightbox with ESC
    if (e.keyCode === 27) {
        plugin.close();
    }
    // Go to next image pressing the right key
    if (e.keyCode === 39) {
        plugin.next();
    }
    // Go to previous image pressing the left key
    if (e.keyCode === 37) {
        plugin.previous();
    }
}

and need to add:
$(document).on('keydown', plugin.keyDownEvent);

and to remove only this function:
$(document).unbind('keydown', plugin.keyDownEvent);