diff --git a/platform/firefox/frameModule.js b/platform/firefox/frameModule.js
index 5b90d5d..a1de19a 100644
--- a/platform/firefox/frameModule.js
+++ b/platform/firefox/frameModule.js
@@ -168,6 +168,9 @@ const contentObserver = {
             type: type,
             url: location.spec
         };
+        if ( type === 7 ) {
+            details.attrSrc = context.frameElement.getAttribute('src');
+        }
 
         if ( typeof messageManager.sendRpcMessage === 'function' ) {
             // https://bugzil.la/1092216