initial, window.getSelection().toString() is ""
after selecting foo, window.getSelection().toString() is "foo"
after selecting bar, window.getSelection().toString() is "bar"
after unselecting bar, window.getSelection().toString() is ""
after selecting 'z' from normal text input, window.getSelection().toString() is "z"
after selecting 'boo' from password input, window.getSelection().toString() is "•••"