history-back-with-fallback.js

var historyBackWithFallback = function(url){
    var originalHref = window.location.href;

    var timeoutId = setTimeout(function(){
        if(window.location.href !== originalHref){
            return;
        }
        window.location = 'https://google.de';
    }, 1500);
    
    window.addEventListener('beforeunload', function(){
        clearTimeout(timeoutId);
    });

    history.back();
}