diff --git a/src/content/content.js b/src/content/content.js
index 43827a2..29330b7 100644
--- a/src/content/content.js
+++ b/src/content/content.js
@@ -118,8 +118,8 @@ notifyPage();
 addEventListener("DOMContentLoaded", e => {
   if (ns.canScript) return;
   for (let m of document.querySelectorAll("meta[http-equiv=refresh]")) {
-    if (/^[^,;]*[,;]url[^\w=]*=\s*data:/.test(m.getAttribute("content"))) {
-      let url = m.getAttribute("content").replace(/.*?(?=data:)/, "");
+    if (/^[^,;]*[,;]\W*url[^=]*=[^!#$%&'()*+,/:;=?@[\]\w.,~-]*data:/i.test(m.getAttribute("content"))) {
+      let url = m.getAttribute("content").replace(/.*?(?=data:)/i, "");
       log(`Blocking refresh to ${url}`);
       window.stop();
     }