diff --git a/Tests/LibWeb/TestConfig.ini b/Tests/LibWeb/TestConfig.ini
index ad8863712a..24bea23b45 100644
--- a/Tests/LibWeb/TestConfig.ini
+++ b/Tests/LibWeb/TestConfig.ini
@@ -1,4 +1,3 @@
 [Skipped]
-Text/input/HTML/Window-postMessage.html
 Text/input/Worker/Worker-echo.html
 Text/input/window-scrollTo.html
diff --git a/Tests/LibWeb/Text/input/HTML/Window-postMessage.html b/Tests/LibWeb/Text/input/HTML/Window-postMessage.html
index ec8f9608d6..153eaa0952 100644
--- a/Tests/LibWeb/Text/input/HTML/Window-postMessage.html
+++ b/Tests/LibWeb/Text/input/HTML/Window-postMessage.html
@@ -127,11 +127,21 @@
         globalThis.doneCallback = done;
 
         const blobIframeLoadPromise = new Promise(resolve => {
-            blobIframe.onload = () => resolve();
+            if (blobIframe.contentDocument.readyState === "complete") {
+                resolve();
+            }
+            else {
+                blobIframe.onload = () => resolve();
+            }
         });
 
         const srcdocIframeLoadPromise = new Promise(resolve => {
-            iframe.onload = () => resolve();
+            if (iframe.contentDocument.readyState === "complete") {
+                resolve()
+            }
+            else {
+                iframe.onload = () => resolve();
+            }
         });
 
         Promise.all([blobIframeLoadPromise, srcdocIframeLoadPromise]).then(() => {