diff --git a/pages/API/resize-observer/resize-observer.uvue b/pages/API/resize-observer/resize-observer.uvue
index a40cb8fc0dba11d332c2d9c6a4cd7db3b30b1052..eeeeed112ba6414c642d87e0dc620eb926e04bc3 100644
--- a/pages/API/resize-observer/resize-observer.uvue
+++ b/pages/API/resize-observer/resize-observer.uvue
@@ -56,11 +56,11 @@
         })
         this.outBoxElement = uni.getElementById("outBox")
         if (this.outBoxElement != null) {
-          this.resizeObserver!.observe(this.outBoxElement)
+          this.resizeObserver!.observe(this.outBoxElement!)
         }
         this.innerBoxElement = uni.getElementById("innerBox")
         if (this.innerBoxElement != null) {
-          this.resizeObserver!.observe(this.innerBoxElement)
+          this.resizeObserver!.observe(this.innerBoxElement!)
         }
       }
     },