diff --git a/lib/mobile_fu.rb b/lib/mobile_fu.rb
index 70c6163..a059206 100644
--- a/lib/mobile_fu.rb
+++ b/lib/mobile_fu.rb
@@ -69,7 +69,7 @@ def force_mobile_format
       # the user has opted to use either the 'Standard' view or 'Mobile' view.
 
       def set_mobile_format
-        if is_mobile_device? && !request.xhr?
+        if request.format.html? && is_mobile_device? && !request.xhr?
           request.format = session[:mobile_view] == false ? :html : :mobile
           session[:mobile_view] = true if session[:mobile_view].nil?
         end