diff --git a/src/popover/demo/index.vue b/src/popover/demo/index.vue
index c279f6af0..2ff184a6f 100644
--- a/src/popover/demo/index.vue
+++ b/src/popover/demo/index.vue
@@ -45,6 +45,7 @@
         <div class="demo-popover-box">
           <van-popover
             v-model="show.placement"
+            theme="dark"
             :actions="t('shortActions')"
             :placement="currentPlacement"
           >
diff --git a/src/popover/index.js b/src/popover/index.js
index 3b5c35f67..a06ea3522 100644
--- a/src/popover/index.js
+++ b/src/popover/index.js
@@ -1,5 +1,6 @@
 import { createPopper } from '@popperjs/core/lib/popper-lite';
 import offsetModifier from '@popperjs/core/lib/modifiers/offset';
+import extendsHelper from '@babel/runtime/helpers/esm/extends';
 import { createNamespace } from '../utils';
 import { BORDER_BOTTOM } from '../utils/constant';
 
@@ -10,6 +11,12 @@ import { ClickOutsideMixin } from '../mixins/click-outside';
 import Icon from '../icon';
 import Popup from '../popup';
 
+// add Object.assign polyfill for popper.js
+// see: https://popper.js.org/docs/v2/browser-support/
+if (!Object.assign) {
+  Object.assign = extendsHelper;
+}
+
 const [createComponent, bem] = createNamespace('popover');
 
 export default createComponent({