diff --git a/lms/templates/courseware/courseware-chromeless.html b/lms/templates/courseware/courseware-chromeless.html
index 466b99bfe132587e694992d3716837db0b30586c..0abee7697e0f3abdacb0992bc8ae88f346c1c0e2 100644
--- a/lms/templates/courseware/courseware-chromeless.html
+++ b/lms/templates/courseware/courseware-chromeless.html
@@ -50,13 +50,12 @@ ${static.get_page_title_breadcrumbs(course_name())}
     // If this chromeless view is in an iframe in the learning microfrontend app
     // then add a base tag in the head (of the iframe document) to force links
     // in this iframe to navigate the parent window.
-    if (window !== window.parent) {
-      var learningAppReferrer = "${settings.LEARNING_MICROFRONTEND_URL | n, js_escaped_string}";
-      if (document.referrer === learningAppReferrer) {
-        var baseElement = document.createElement('base');
-        baseElement.setAttribute('target', '_parent');
-        document.head.appendChild(baseElement);
-      }
+    var learningAppUrl = "${settings.LEARNING_MICROFRONTEND_URL | n, js_escaped_string}";
+    var parentIsLearningApp = document.referrer.indexOf(learningAppUrl) === 0;
+    if (window !== window.parent && parentIsLearningApp) {
+      var baseElement = document.createElement('base');
+      baseElement.setAttribute('target', '_parent');
+      document.head.appendChild(baseElement);
     }
   </script>
 </%block>
@@ -112,44 +111,43 @@ ${HTML(fragment.foot_html())}
     // If this view is rendered in an iframe within the learning microfrontend app
     // it will report the height of its contents to the parent window when the
     // document loads, window resizes, or DOM mutates.
-    if (window !== window.parent) {
-      var learningAppReferrer = "${settings.LEARNING_MICROFRONTEND_URL | n, js_escaped_string}";
-      if (document.referrer === learningAppReferrer) {
-
-        var lastHeight = window.offsetHeight;
-        var lastWidth = window.offsetWidth;
-        var contentElement = document.getElementById('content');
-
-        function dispatchResizeMessage() {
-          var newHeight = contentElement.offsetHeight;
-          var newWidth = contentElement.offsetWidth;
-
-          if (newWidth === lastWidth && newHeight === lastHeight) {
-            return;
-          }
-
-          window.parent.postMessage({
-              type: 'plugin.resize',
-              payload: {
-                width: newWidth,
-                height: newHeight,
-              }
-            }, document.referrer
-          );
-
-          lastHeight = newHeight;
-          lastWidth = newWidth;
-        }
+    var learningAppUrl = "${settings.LEARNING_MICROFRONTEND_URL | n, js_escaped_string}";
+    var parentIsLearningApp = document.referrer.indexOf(learningAppUrl) === 0;
 
-        // Create an observer instance linked to the callback function
-        const observer = new MutationObserver(dispatchResizeMessage);
+    if (window !== window.parent && parentIsLearningApp) {
+      var lastHeight = window.offsetHeight;
+      var lastWidth = window.offsetWidth;
+      var contentElement = document.getElementById('content');
 
-        // Start observing the target node for configured mutations
-        observer.observe(document.body, { attributes: true, childList: true, subtree: true });
+      function dispatchResizeMessage() {
+        var newHeight = contentElement.offsetHeight;
+        var newWidth = contentElement.offsetWidth;
+
+        if (newWidth === lastWidth && newHeight === lastHeight) {
+          return;
+        }
 
-        window.addEventListener('load', dispatchResizeMessage);
-        window.addEventListener('resize', dispatchResizeMessage);
+        window.parent.postMessage({
+            type: 'plugin.resize',
+            payload: {
+              width: newWidth,
+              height: newHeight,
+            }
+          }, document.referrer
+        );
+
+        lastHeight = newHeight;
+        lastWidth = newWidth;
       }
+
+      // Create an observer instance linked to the callback function
+      const observer = new MutationObserver(dispatchResizeMessage);
+
+      // Start observing the target node for configured mutations
+      observer.observe(document.body, { attributes: true, childList: true, subtree: true });
+
+      window.addEventListener('load', dispatchResizeMessage);
+      window.addEventListener('resize', dispatchResizeMessage);
     }
   }());
 </script>