diff --git a/debug/iframe-blob.html b/debug/iframe-blob.html
new file mode 100644
index 00000000000..d9d9b5e7074
--- /dev/null
+++ b/debug/iframe-blob.html
@@ -0,0 +1,54 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <title>Mapbox GL JS debug page</title>
+    <meta charset='utf-8'>
+    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no">
+</head>
+
+<body>
+
+<iframe width="800" height="600"></iframe>
+<script>let mapboxgl = {};</script>
+<script src='access_token_generated.js'></script>
+<script>
+let js = document.createElement("a");
+js.href = "../dist/mapbox-gl-dev.js";
+let css = document.createElement("a");
+css.href = "../dist/mapbox-gl.css";
+document.querySelector('iframe').src = URL.createObjectURL(new Blob([ `
+<!DOCTYPE html>
+<html>
+<head>
+    <title>Mapbox GL JS debug page</title>
+    <meta charset='utf-8'>
+    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no">
+    <link rel='stylesheet' href='${css.href}' />
+    <style>
+        body { margin: 0; padding: 0; }
+        html, body, #map { height: 100%; }
+    </style>
+</head>
+
+<body>
+<div id='map'></div>
+
+<script src='${js.href}'><\/script>
+<script>
+mapboxgl.accessToken = '${mapboxgl.accessToken}';
+var map = window.map = new mapboxgl.Map({
+    container: 'map',
+    zoom: 12.5,
+    center: [-77.01866, 38.888],
+    style: 'mapbox://styles/mapbox/streets-v10',
+    hash: true
+});
+
+<\/script>
+</body>
+</html>
+` ], {type: 'text/html'}));
+</script>
+
+</body>
+</html>
diff --git a/debug/iframe.html b/debug/iframe.html
new file mode 100644
index 00000000000..6e4fe349fac
--- /dev/null
+++ b/debug/iframe.html
@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <title>Mapbox GL JS debug page</title>
+    <meta charset='utf-8'>
+    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no">
+</head>
+
+<body>
+
+<iframe width="800" height="600" src="index.html"></iframe>
+
+</body>
+</html>
diff --git a/src/util/ajax.js b/src/util/ajax.js
index 61853f8ef29..cf947949cea 100644
--- a/src/util/ajax.js
+++ b/src/util/ajax.js
@@ -84,12 +84,7 @@ function isWorker() {
 /* global self, WorkerGlobalScope */
 export const getReferrer = isWorker() ?
     () => self.worker && self.worker.referrer :
-    () => {
-        const origin = window.location.origin;
-        if (origin && origin !== 'null' && origin !== 'file://') {
-            return origin + window.location.pathname;
-        }
-    };
+    () => (location.protocol === 'blob:' ? parent : window).location.href;
 
 function makeFetchRequest(requestParameters: RequestParameters, callback: ResponseCallback<any>): Cancelable {
     const controller = new window.AbortController();
