diff --git a/bin/cmd.js b/bin/cmd.js
index f9bee98..c06eeb1 100755
--- a/bin/cmd.js
+++ b/bin/cmd.js
@@ -258,7 +258,7 @@ function getHTML (cb) {
         after = '<script>mocha.run()</script>';
     }
     
-    cb('<html><head><meta charset="utf-8"></head><body>'
+    cb('<!DOCTYPE html>\n<html><head><meta charset="utf-8"></head><body>'
         + '<pre id="__testling_output"></pre>'
         + '<script>' + prelude + '</script>'
         + before
