diff --git a/lib/mathjax/rails/controllers.rb b/lib/mathjax/rails/controllers.rb
index ea613073d..05b761cd8 100644
--- a/lib/mathjax/rails/controllers.rb
+++ b/lib/mathjax/rails/controllers.rb
@@ -12,6 +12,7 @@ def giveOutStaticFile
     options[:disposition] = 'inline'
     file = File.expand_path(filepath, __FILE__)
     if File.exists?(file)
+      expires_in (params[:cache] || 1.day), :public => true unless params[:cache] == false
       send_file file, options
     else
       render :status => 404
diff --git a/lib/mathjax/rails/routes.rb b/lib/mathjax/rails/routes.rb
index ed4c533a2..3f78b5e4f 100644
--- a/lib/mathjax/rails/routes.rb
+++ b/lib/mathjax/rails/routes.rb
@@ -1,8 +1,8 @@
 module Mathjax
   module Rails
     module RouterMethods
-      def mathjax(str)
-        match "#{str}/*uri" => "mathjax/rails/mathjax_rails#giveOutStaticFile",:as=>'mathjax', :via => [:get, :post]
+      def mathjax(str, cache=1.day)
+        match "#{str}/*uri" => "mathjax/rails/mathjax_rails#giveOutStaticFile",:as=>'mathjax', :via => [:get, :post], :cache => cache
       end
     end
   end