diff --git a/src/main/scala/org/scalajs/dom/raw/lib.scala b/src/main/scala/org/scalajs/dom/raw/lib.scala
index 77a6c1785..c28906c17 100644
--- a/src/main/scala/org/scalajs/dom/raw/lib.scala
+++ b/src/main/scala/org/scalajs/dom/raw/lib.scala
@@ -2566,6 +2566,8 @@ class Window
    */
   def close(): Unit = js.native
 
+  def closed: Boolean = js.native
+
   /**
    * The window.postMessage method safely enables cross-origin communication.
    * Normally, scripts on different pages are allowed to access each other if and only if