Update article.md

leviding · web-flow · commit 61f6a21929bf · 2019-07-01T09:48:22.000+08:00
diff --git a/2-ui/5-loading/01-onload-ondomcontentloaded/article.md b/2-ui/5-loading/01-onload-ondomcontentloaded/article.md
@@ -170,7 +170,6 @@ window.addEventListener("unload", function() {
 ```js run
 window.onbeforeunload = function() {
   return false;
-  return "There are unsaved changes. Leave now?";
 };
 ```
 
