diff --git a/src/Filtering/Filter.coffee b/src/Filtering/Filter.coffee
index 1c69730d4..156c47cca 100755
--- a/src/Filtering/Filter.coffee
+++ b/src/Filtering/Filter.coffee
@@ -127,7 +127,7 @@ Filter =
         return true if result.hide
     false
 
-  postID:     (post) -> post.ID ? post.postID
+  postID:     (post) -> "#{post.ID ? post.postID}"
   name:       (post) -> post.info.name
   uniqueID:   (post) -> post.info.uniqueID
   tripcode:   (post) -> post.info.tripcode