Scroll to top.js

function scrollToTop($topClass){   
    var top_0 = {scrollTop:0};
    var topClass = $($topClass);
    topClass.on("click" , function(e){
        $("html,body").animate(top_0,1000);
        return false;
    });
    $(window).scroll(function(){
        if($(this).scrollTop() > 400) {
            topClass.fadeIn(500);
        }
        else {
            topClass.fadeOut(500);
        }
    });
}
scrollToTop('.scrolltotop i');