1 files changed, 8 insertions, 7 deletions
diff --git a/lib/sisu/v4/epub_format.rb b/lib/sisu/v4/epub_format.rb
index 49139667..683228c3 100644
--- a/lib/sisu/v4/epub_format.rb
+++ b/lib/sisu/v4/epub_format.rb
@@ -70,25 +70,26 @@ module SiSU_EPUB_Format
       make=SiSU_Env::ProcessingSettings.new(@md)
       if make.build.ocn?
         ocn_class='ocn'
-        if @ocn.to_i==0
-          @ocn.gsub(/^(\d+|)$/,'')
+        if @ocn==nil \
+        or @ocn.to_i==0 \
+        or @ocn.empty?
+          %{<label class="ocn_off"></label>}
         else
           @ocn.gsub(/^(\d+|)$/,
             %{<label class="#{ocn_class}"><a href="#o\\1" class="lnk#{ocn_class}">\\1</a></label>})
         end
       else
-        ocn_class='ocn_off'
-        @ocn.gsub(/^(\d+|)$/,'')
+        %{<label class="ocn_off"></label>}
       end
     end
     def name
-      %{<a name="#{@ocn}"></a>}
+      (@ocn==nil || @ocn.empty?) ? '' : %{<a name="#{@ocn}"></a>}
     end
     def id #w3c? "tidy" complains about numbers as identifiers ! annoying
-      (@ocn.empty?) ? '' : %{id="o#{@ocn}"}
+      (@ocn==nil || @ocn.empty?) ? '' : %{id="o#{@ocn}"}
     end
     def goto
-      %{<a href="##{@ocn}">}
+      (@ocn==nil || @ocn.empty?) ? '' : %{<a href="##{@ocn}">}
     end
   end
   class CSS