diff --git a/src/ui/js/diff2html-ui.js b/src/ui/js/diff2html-ui.js
index 42e2266..fb18f2b 100644
--- a/src/ui/js/diff2html-ui.js
+++ b/src/ui/js/diff2html-ui.js
@@ -109,13 +109,9 @@
           result.value = mergeStreams(originalStream, nodeStream(resultNode), text);
         }
 
-        buildClassName(line.className, result.language)
-          .split(" ")
-          .map(function(className) {
-            $line.addClass(className);
-          });
+        $line.addClass("hljs");
+        $line.addClass(result.language);
         $line.html(result.value);
-
       });
     });
   };
@@ -207,20 +203,6 @@
    * Will be removed when this part of the API is exposed
    */
 
-  function buildClassName(prevClassName, language) {
-    var result = [prevClassName.trim()];
-
-    if (!prevClassName.match(/\bhljs\b/)) {
-      result.push('hljs');
-    }
-
-    if (prevClassName.indexOf(language) === -1) {
-      result.push(language);
-    }
-
-    return result.join(' ').trim();
-  }
-
   /* Utility functions */
 
   function escape(value) {