diff --git a/plugins/postcss-focus-within/src/browser.js b/plugins/postcss-focus-within/src/browser.js
index 6a225a7bd2..72234467f2 100644
--- a/plugins/postcss-focus-within/src/browser.js
+++ b/plugins/postcss-focus-within/src/browser.js
@@ -65,7 +65,11 @@ export default function focusWithin(opts) {
const handleFocusChange = generateHandler(options.replaceWith);
const initialize = function initializeEventListeners() {
- document.documentElement.classList.add('js-focus-within');
+ if (document.documentElement.className.indexOf('js-focus-within') > -1) {
+ return;
+ }
+
+ document.documentElement.className = document.documentElement.className + ' js-focus-within';
document.addEventListener('focus', handleFocusChange, true);
document.addEventListener('blur', handleFocusChange, true);
};
diff --git a/plugins/postcss-focus-within/test/_browser.html b/plugins/postcss-focus-within/test/_browser.html
index c184557348..0332a325f4 100644
--- a/plugins/postcss-focus-within/test/_browser.html
+++ b/plugins/postcss-focus-within/test/_browser.html
@@ -7,6 +7,7 @@
+