Smooth scrolling to a hash plus a scroll class to scroll only those links

custom.js

// Smooth scrolling to a hash  (For links to work you need to add class .scroll)

var hashTagActive = "";
$(".scroll").on("click touchstart" , function (event) {
    if(hashTagActive != this.hash) { //this will prevent if the user click several times the same link to freeze the scroll.
        event.preventDefault();
        //calculate destination place
        var dest = 0;
        if ($(this.hash).offset().top > $(document).height() - $(window).height()) {
            dest = $(document).height() - $(window).height();
        } else {
            dest = $(this.hash).offset().top;
        }
        //go to destination
        $('html,body').animate({
            scrollTop: dest
        }, 500, 'swing');
        hashTagActive = this.hash;
    }
});