diff --git a/js/main.js b/js/main.js
index 816d021a..dfb79708 100644
--- a/js/main.js
+++ b/js/main.js
@@ -245,7 +245,7 @@ const MM = (function () {
 		if (moduleWrapper !== null) {
 			moduleWrapper.style.transition = "opacity " + speed / 1000 + "s";
 			moduleWrapper.style.opacity = 0;
-			moduleWrapper.className += " hidden";
+			moduleWrapper.classList.add("hidden");
 
 			clearTimeout(module.showHideTimer);
 			module.showHideTimer = setTimeout(function () {
@@ -311,7 +311,7 @@ const MM = (function () {
 			moduleWrapper.style.transition = "opacity " + speed / 1000 + "s";
 			// Restore the position. See hideModule() for more info.
 			moduleWrapper.style.position = "static";
-			moduleWrapper.className = moduleWrapper.className.split(" hidden").join("");
+			moduleWrapper.classList.remove("hidden");
 
 			updateWrapperStates();