$(window).on( 'blur.wp-heartbeat-focus', function() {
                setFrameFocusEvents();
                // We don't know why the 'blur' was fired. Either the user clicked in an iframe or outside the browser.
                // Running blurred() after some timeout lets us cancel it if the user clicked in an iframe.
                settings.winBlurTimer = window.setTimeout( function(){ blurred(); }, 500 );