html: Asynchrones Google Analytics with OptOut.html

<!-- Google Analytics: change UA-XXXXX-Y to be your site's ID. -->
    <script>
        var gaProperty = 'UA-XXXXX-Y';

        window.ga=function(){ga.q.push(arguments)};ga.q=[];ga.l=+new Date;
        ga('create', gaProperty,'auto');
        ga('set','anonymizeIp',true);
        ga('send','pageview');

        var disableStr = 'ga-disable-' + gaProperty;
        if (document.cookie.indexOf(disableStr + '=true') > -1) {
            window[disableStr] = true;
        }
        function gaOptout() {
            document.cookie = disableStr + '=true; expires=Thu, 31 Dec 2099 23:59:59 UTC; path=/';
            window[disableStr] = true;
            alert('Google Analytics wurde für diese Seite deaktiviert!');
        }
    </script>
    <script src="https://www.google-analytics.com/analytics.js" async defer></script>