Make the description more accurate

ColinTree · web-flow · commit 31895a91f6b0 · 2018-03-27T14:40:03.000+08:00
diff --git a/README.md b/README.md
@@ -51,6 +51,6 @@ e.g.
 {% Ai2Property %}{"name":"PropertyName2", "getter":false}{% endAi2Property %}
 ```
 
-will be converted into:
+will be converted into: (after web page loaded)
 
 ![](example.png)
