补全scroll时class控制

@@ -61,31 +61,30 @@ exports.init = function() {
         $(document).scroll(function() {
             var sTop = $(this).scrollTop();
 
-            //Tip: removeClass只用移除相邻状态即可
             if (sTop <= containerTop - wH + tContainerH) {
                 thumbContainer
                     .addClass('fixed-bottom')
-                    .removeClass('static');
+                    .removeClass('static fixed-top absolute');
             } else if (sTop <= containerTop) {
                 thumbContainer
                     .addClass('static')
-                    .removeClass('fixed-bottom fixed-top');
+                    .removeClass('fixed-bottom fixed-top absolute');
             } else if (sTop <= containerTop + containerH - tContainerH) {
                 thumbContainer
                     .addClass('fixed-top')
-                    .removeClass('static absolute')
+                    .removeClass('static absolute fixed-bottom')
                     .removeAttr('style');
             } else if (sTop < containerTop + containerH) {
                 thumbContainer
                     .addClass('absolute')
-                    .removeClass('static fixed-top')
+                    .removeClass('static fixed-top fixed-bottom')
                     .css({
                         top: containerTop + containerH - tContainerH
                     });
             } else if (sTop > containerTop + containerH) {
                 thumbContainer
                     .addClass('static')
-                    .removeClass('absolute')
+                    .removeClass('absolute fixed-top fixed-bottom')
                     .removeAttr('style');
             }
         });