diff --git a/spug_web/src/pages/deploy/do/OutView.js b/spug_web/src/pages/deploy/do/OutView.js
index 0d31faa..d977bc0 100644
--- a/spug_web/src/pages/deploy/do/OutView.js
+++ b/spug_web/src/pages/deploy/do/OutView.js
@@ -18,7 +18,9 @@ class OutView extends React.Component {
   }
 
   componentDidUpdate(prevProps, prevState, snapshot) {
-    setTimeout(() => this.el.scrollTop = this.el.scrollHeight, 100)
+    setTimeout(() => {
+      if (this.el) this.el.scrollTop = this.el.scrollHeight
+    }, 100)
   }
 
   render() {
diff --git a/spug_web/src/pages/exec/task/OutView.js b/spug_web/src/pages/exec/task/OutView.js
index ee55020..d85ba5f 100644
--- a/spug_web/src/pages/exec/task/OutView.js
+++ b/spug_web/src/pages/exec/task/OutView.js
@@ -16,7 +16,9 @@ class OutView extends React.Component {
   }
 
   componentDidUpdate(prevProps, prevState, snapshot) {
-    setTimeout(() => this.el.scrollTop = this.el.scrollHeight, 100)
+    setTimeout(() => {
+      if (this.el) this.el.scrollTop = this.el.scrollHeight
+    }, 100)
   }
 
   render() {