diff --git a/danmaku2ass.py b/danmaku2ass.py
index 044abc5..6ec70b4 100755
--- a/danmaku2ass.py
+++ b/danmaku2ass.py
@@ -181,15 +181,16 @@ def ReadCommentsBilibili(f, fontsize):
             p = str(comment.getAttribute('p')).split(',')
             assert len(p) >= 5
             assert p[1] in ('1', '4', '5', '6', '7', '8')
-            if p[1] in ('1', '4', '5', '6'):
-                c = str(comment.childNodes[0].wholeText).replace('/n', '\n')
-                size = int(p[2])*fontsize/25.0
-                yield (float(p[0]), int(p[4]), i, c, {'1': 0, '4': 2, '5': 1, '6': 3}[p[1]], int(p[3]), size, (c.count('\n')+1)*size, CalculateLength(c)*size)
-            elif p[1] == '7':  # positioned comment
-                c = str(comment.childNodes[0].wholeText)
-                yield (float(p[0]), int(p[4]), i, c, 'bilipos', int(p[3]), int(p[2]), 0, 0)
-            elif p[1] == '8':
-                pass  # ignore scripted comment
+            if comment.childNodes.length > 0:
+                if p[1] in ('1', '4', '5', '6'):
+                    c = str(comment.childNodes[0].wholeText).replace('/n', '\n')
+                    size = int(p[2])*fontsize/25.0
+                    yield (float(p[0]), int(p[4]), i, c, {'1': 0, '4': 2, '5': 1, '6': 3}[p[1]], int(p[3]), size, (c.count('\n')+1)*size, CalculateLength(c)*size)
+                elif p[1] == '7':  # positioned comment
+                    c = str(comment.childNodes[0].wholeText)
+                    yield (float(p[0]), int(p[4]), i, c, 'bilipos', int(p[3]), int(p[2]), 0, 0)
+                elif p[1] == '8':
+                    pass  # ignore scripted comment
         except (AssertionError, AttributeError, IndexError, TypeError, ValueError):
             logging.warning(_('Invalid comment: %s') % comment.toxml())
             continue