Your link also only gets 99/100 on modern browsers.

Why? Well...

    // test 64: more attribute tests
    // attributes of the <object> element
    var obj1 = document.createElement('object');
    obj1.setAttribute('data', 'test.html');
    // ...
    assert(obj1.data.match(/^http:/), "object.data isn't absolute");

See that "http" in test 64? Turns out you'll get a score of 100/100 if you use the http version of the URL instead of HTTPS.