diff --git a/docs/create-modify-element.mdx b/docs/create-modify-element.mdx
index 3cad265..caa40f9 100644
--- a/docs/create-modify-element.mdx
+++ b/docs/create-modify-element.mdx
@@ -221,6 +221,7 @@ var fragment = document.createDocumentFragment()
 // Insert / modify elements in fragment
 
 // in dom, <div class="outer"/>
+var outerEle = document.querySelector(".outer")
 
 outerEle.appendChild(fragment)
 // This will remove all content from fragment and