fix go back top button

assets/javascripts/app.js

@@ -328,7 +328,8 @@
       // 回到頁面最頂端，動態產生DOM
       // txt = 按鈕的文字, speed = 捲動時的速度
       goBackTop: function(txt, speed) {
-        var top = document.createElement('div');
+        var top = document.createElement('a');
+        top.href = '#gotocenter';
         top.className = 'go-back-top no-print';
         top.textContent = txt || 'top';
         doc.body.appendChild(top);
@@ -348,17 +349,10 @@
 
 
         // 捲動效果
-        $('.go-back-top').on('click', function() {
+        $('.go-back-top .top').on('click', function() {
           $('body, html').animate({
             scrollTop: 0
           }, speed || 300);
-          return false;
-        });
-        $('.top').on('click', function() {
-          $('body, html').animate({
-            scrollTop: 0
-          }, speed || 300);
-          return false;
         });
 
       },