diff --git a/seahub/templates/repo.html b/seahub/templates/repo.html
index 4c98d5447f..a325c49076 100644
--- a/seahub/templates/repo.html
+++ b/seahub/templates/repo.html
@@ -2370,7 +2370,7 @@ function updateCmt() {
 {% endif %}
 
 {% if not repo.encrypted and ENABLE_THUMBNAIL %}
-var timer,
+var timer, ajaxRequest = $.ajax(),
     default_size = {{PREVIEW_DEFAULT_SIZE}},
     preview_wrap = $('<div id="preview-wrap"><img id="image-preview" src="" alt=""/><div class="outer-caret right-outer-caret"><div class="inner-caret"></div></div></div>')
         .appendTo("body")
@@ -2385,50 +2385,59 @@ $("#repo-file-list").on({
             file_item = thumbnail.closest('.file-item');
 
         timer = setTimeout(function () {
-            $.ajax({
-            url: '{% url 'thumbnail_create' repo.id %}?path=' + e(cur_path+file_item.attr('data-name')) + '&size=' + default_size,
-            cache: false,
-            dataType: 'json',
-            success: function(data) {
-                image_preview.attr("src", data.thumbnail_src);
+            ajaxRequest = $.ajax({
+                url: '{% url 'thumbnail_create' repo.id %}?path=' + e(cur_path+file_item.attr('data-name')) + '&size=' + default_size,
+                cache: false,
+                dataType: 'json',
+                success: function(data) {
+                    image_preview.attr("src", data.thumbnail_src);
 
-                var file_item_offset = file_item.offset(),
-                    thumbnail_offset = thumbnail.offset(),
+                    var file_item_offset = file_item.offset(),
+                        thumbnail_offset = thumbnail.offset(),
 
-                    wrap_width = preview_wrap.outerWidth(),
-                    wrap_padding = parseInt(preview_wrap.css('padding-top')),
+                        wrap_width = preview_wrap.outerWidth(),
+                        wrap_padding = parseInt(preview_wrap.css('padding-top')),
 
-                    caret_width = parseInt(caret.css('border-top-width')),
-                    caret_pos_x = (default_size)/2 + wrap_padding - caret_width,
-                    caret_pos_y = default_size + 2 * wrap_padding,
+                        caret_width = parseInt(caret.css('border-top-width')),
+                        caret_pos_x = (default_size)/2 + wrap_padding - caret_width,
+                        caret_pos_y = default_size + 2 * wrap_padding,
 
-                    wrap_left = file_item_offset.left - wrap_width - caret_width;
+                        wrap_left = file_item_offset.left - wrap_width - caret_width;
 
-                if (wrap_left >= 0) {
-                    caret.removeClass('bottom-outer-caret')
-                        .addClass('right-outer-caret')
-                        .css({'top':caret_pos_x + 'px', 'left':caret_pos_y + 'px'});
+                    if (wrap_left >= 0) {
+                        caret.removeClass('bottom-outer-caret')
+                            .addClass('right-outer-caret')
+                            .css({'top':caret_pos_x + 'px', 'left':caret_pos_y + 'px'});
 
-                    preview_wrap.css({
-                        'top'  : (thumbnail_offset.top + (thumbnail.height() - wrap_width)/2) + 'px',
-                        'left' : wrap_left + 'px'
-                    }).fadeIn();
-                } else {
-                    caret.removeClass("right-outer-caret")
-                         .addClass("bottom-outer-caret")
-                         .css({'top':caret_pos_y + 'px', 'left':caret_pos_x + 'px'});
+                        preview_wrap.css({
+                            'top'  : (thumbnail_offset.top + (thumbnail.height() - wrap_width)/2) + 'px',
+                            'left' : wrap_left + 'px'
+                        }).fadeIn();
+                    } else {
+                        caret.removeClass("right-outer-caret")
+                             .addClass("bottom-outer-caret")
+                             .css({'top':caret_pos_y + 'px', 'left':caret_pos_x + 'px'});
 
-                    preview_wrap.css({
-                        'top'  : (file_item_offset.top - wrap_width) - caret_width + 'px',
-                        'left' : (thumbnail_offset.left + (thumbnail.width() - wrap_width)/2) + 'px'
-                    }).fadeIn();
+                        preview_wrap.css({
+                            'top'  : (file_item_offset.top - wrap_width) - caret_width + 'px',
+                            'left' : (thumbnail_offset.left + (thumbnail.width() - wrap_width)/2) + 'px'
+                        }).fadeIn();
+                    }
+                },
+                error: function(xhr, textStatus, errorThrown) {
+                   if (textStatus != "abort") {
+                       if (xhr.responseText) {
+                           feedback($.parseJSON(xhr.responseText).error, 'error');
+                       } else {
+                           feedback("{% trans "Failed. Please check the network." %}", 'error');
+                       };
+                   };
                 }
-            },
-            error: ajaxErrorHandler
             });
         }, 200);
     },
     mouseleave: function() {
+        ajaxRequest.abort();
         clearTimeout(timer);
         preview_wrap.hide();
         image_preview.attr('src', ''); // for ff. In ff, when hover, the last preview image would be shown first, then the right one.