FileAPI/support/incumbent.sub.html

<!DOCTYPE html>
<title>Incumbent page used as a test helper</title>

<iframe src="//{{domains[www1]}}:{{location[port]}}/FileAPI/support/document-domain-setter.sub.html" id="c"></iframe>
<iframe src="//{{domains[www2]}}:{{location[port]}}/FileAPI/support/document-domain-setter.sub.html" id="r"></iframe>
<iframe src="//{{domains[élève]}}:{{location[port]}}/FileAPI/support/document-domain-setter.sub.html" id="bs"></iframe>

<script>
"use strict";
document.domain = "{{host}}";

window.createBlobURL = () => {
    const current = document.querySelector("#c").contentWindow;
    const relevant = document.querySelector("#r").contentWindow;
    const blobSource = document.querySelector("#bs").contentWindow;

    const blob = new blobSource.Blob(["Test Blob"]);

    return current.URL.createObjectURL.call(relevant, blob);
};

</script>