diff --git a/lib/docs/filters/axios/clean_html.rb b/lib/docs/filters/axios/clean_html.rb
index 7a1aa8cc..e09c7ef4 100644
--- a/lib/docs/filters/axios/clean_html.rb
+++ b/lib/docs/filters/axios/clean_html.rb
@@ -3,6 +3,10 @@ module Docs
     class CleanHtmlFilter < Filter
       def call
         css('.links').remove
+        css('pre').each do |node|
+          node.content = node.content
+          node['data-language'] = node['class'][/lang-(\w+)/, 1]
+        end
         doc
       end
     end