js méthode setinterval pour modifier la période d'exécution

function setDeceleratingTimeout(callback, factor, times){
    var internalCallback = function(tick, counter) {
        return function() {
            if (--tick >= 0) {
                window.setTimeout(internalCallback, ++counter * factor);
                callback();
            }
        }
    }(times, 0);

    window.setTimeout(internalCallback, factor);};// console.log() requires firebug  
      setDeceleratingTimeout(function(){ console.log('hi');
      }, 10, 10);setDeceleratingTimeout(function(){ console.log('bye'); }, 100, 10);