diff --git a/docs/start/spec.md b/docs/start/spec.md
index 4636343f0..25827545a 100644
--- a/docs/start/spec.md
+++ b/docs/start/spec.md
@@ -84,3 +84,7 @@ Beware that `src` imports follow the same path resolution rules to CommonJS `req
 ### Syntax Highlighting
 
 Currently there are syntax highlighting support for [Sublime Text](https://github.com/vuejs/vue-syntax-highlight), [Atom](https://atom.io/packages/language-vue), [Vim](https://github.com/posva/vim-vue), [Visual Studio Code](https://marketplace.visualstudio.com/items/liuji-jim.vue) and [Brackets](https://github.com/pandao/brackets-vue). Contributions for other editors/IDEs are highly appreciated! If you are not using any pre-processors in Vue components, you can also get by by treating `*.vue` files as HTML in your editor.
+
+### Comments
+
+Inside each block you shall use the comment syntax of the language being used (HTML, CSS, JavaScript, Jade, etc). For top-level comments, use HTML comment syntax: `<!-- comment contents here -->`