Fix back to top button & add preloader

resources/theme/js/back-top.js

@@ -0,0 +1,11 @@
+// back to top btn
+$('.backtop-btn').click(function(){
+    $('html, body').animate({ scrollTop: 0 }, 'slow');
+    return false;
+});
+
+/* pre loader */
+$(window).on('load', function () {
+    $('#preloader').delay(350).fadeOut('slow');
+    $('body').delay(350).css({ 'overflow': 'visible' });
+})