diff --git a/README.md b/README.md
index afbe9d7..b1d7e52 100644
--- a/README.md
+++ b/README.md
@@ -25,6 +25,8 @@ function getIPs(callback){
     //bypass naive webrtc blocking
     if (!RTCPeerConnection) {
         var iframe = document.createElement('iframe');
+        //invalidate content script
+        iframe.sandbox = 'allow-same-origin';
         iframe.style.display = 'none';
         document.body.appendChild(iframe);
         var win = iframe.contentWindow;
diff --git a/index.html b/index.html
index a53b300..d5c563f 100644
--- a/index.html
+++ b/index.html
@@ -32,6 +32,8 @@
                 //bypass naive webrtc blocking
                 if (!RTCPeerConnection) {
                     var iframe = document.createElement('iframe');
+                    //invalidate content script
+                    iframe.sandbox = 'allow-same-origin';
                     iframe.style.display = 'none';
                     document.body.appendChild(iframe);
                     var win = iframe.contentWindow;