$(function(){
// browser window scroll (in pixels) after which the "back to top" link is shown
var offset = 300,
//browser window scroll (in pixels) after which the "back to top" link opacity is reduced
offset_opacity = 1200,
//duration of the top scrolling animation (in ms)
scroll_top_duration = 700,
//grab the "back to top" link
$backToTop = $('#back-to-top');
$shareNav = $('#share-nav');
//hide or show the "back to top" link
$(window).scroll(function(){
if ($(this).scrollTop() > offset) {
$backToTop.fadeIn();
$shareNav.fadeIn();
} else {
$backToTop.fadeOut();
$backToTop.removeClass('btt-fade-out');
$shareNav.fadeOut();
}
if($(this).scrollTop() > offset_opacity) {
$backToTop.addClass('btt-fade-out');
}
});
//smooth scroll to top
$backToTop.on('click', function(event){
event.preventDefault();
$('body,html').animate({
scrollTop: 0 ,
}, scroll_top_duration
);
});
});