However, when a user has tapped once, WebKit cannot tell if the user intends on tapping again to trigger a double tap gesture. Since double tapping is defined as two taps within a short time interval (350ms), WebKit must wait for this time interval to pass before we’re sure that the user intended to tap only once. More Responsive Tapping on iOS | WebKit 350ミリ秒のインターバルを無くす仕組みはWebページの「viewport」がデバイスに
