var slideIndex = 0;
showSlides();
function showSlides() {
    var i;
    var slides = document.getElementsByClassName("slider");
    for (i = 0; i < slides.length; i++) {
        slides[i].style.display = "none"; 
    }
    slideIndex++;
    if (slideIndex > slides.length) {slideIndex = 1} 
    $(slides[slideIndex-1]).css("display", "block");
    setTimeout(showSlides, 3500);
}