diff --git a/app/calcTextareaHeight.js b/app/calcTextareaHeight.js
index 4607f2cc..2324473d 100644
--- a/app/calcTextareaHeight.js
+++ b/app/calcTextareaHeight.js
@@ -1,5 +1,6 @@
 /**
  * fork from element-ui
+ * https://github.com/ElemeFE/element/blob/master/packages/input/src/calcTextareaHeight.js
  */
 
 let hiddenTextarea;