diff --git a/content/apply.js b/content/apply.js
index 0b5601e4..7ddbce3d 100644
--- a/content/apply.js
+++ b/content/apply.js
@@ -3,7 +3,7 @@
 
 var ID_PREFIX = 'stylus-';
 var ROOT = document.documentElement;
-var isOwnPage = location.href.startsWith('chrome-extension:');
+var isOwnPage = location.protocol.endsWith('-extension:');
 var disableAll = false;
 var exposeIframes = false;
 var styleElements = new Map();