diff --git a/src/plugins/GreaseMonkey/gm_downloader.cpp b/src/plugins/GreaseMonkey/gm_downloader.cpp
index cd2d0eb21..dd84cb526 100644
--- a/src/plugins/GreaseMonkey/gm_downloader.cpp
+++ b/src/plugins/GreaseMonkey/gm_downloader.cpp
@@ -58,6 +58,13 @@ void GM_Downloader::scriptDownloaded()
         return;
     }
 
+    QString contentType = m_reply->header(QNetworkRequest::ContentTypeHeader).toString();
+    if (!(contentType.startsWith(QSL("text/plain")) || contentType.startsWith(QSL("text/javascript")))) {
+        qWarning() << "GreaseMonkey: Unsupported content type" << contentType;
+        Q_EMIT error();
+        return;
+    }
+
     const QByteArray response = QString::fromUtf8(m_reply->readAll()).toUtf8();
 
     if (!response.contains(QByteArray("// ==UserScript=="))) {
diff --git a/src/plugins/GreaseMonkey/gm_plugin.cpp b/src/plugins/GreaseMonkey/gm_plugin.cpp
index 5700e844d..2d467edde 100644
--- a/src/plugins/GreaseMonkey/gm_plugin.cpp
+++ b/src/plugins/GreaseMonkey/gm_plugin.cpp
@@ -107,11 +107,10 @@ bool GM_Plugin::acceptNavigationRequest(WebPage *page, const QUrl &url, QWebEngi
     Q_UNUSED(page)
     Q_UNUSED(isMainFrame)
 
-    bool navigationType = type == QWebEnginePage::NavigationTypeLinkClicked || type == QWebEnginePage::NavigationTypeRedirect;
+    bool navigationType = type == QWebEnginePage::NavigationTypeLinkClicked;
 
-    if (navigationType && url.toString().endsWith(QLatin1String(".user.js"))) {
+    if (navigationType && url.fileName().endsWith(QLatin1String(".user.js"))) {
         m_manager->downloadScript(url);
-        return false;
     }
     return true;
 }