function plusSlides(n){ clearInterval(myTimer); if (n < 0){ showSlides(slideIndex -= 1); } else { showSlides(slideIndex += 1); } if (n === -1){ myTimer = setInterval(function(){plusSlides(n + 2)}, 4000); } else { myTimer = setInterval(function(){plusSlides(n + 1)}, 4000); } }