<pre id="console"></pre>

<script>
if (window.testRunner)
    testRunner.dumpAsText();

window.onerror = function(e) {
	log("onerror saw " + e);
}

try {
    var proto = window.__proto__.__proto__.__proto__;
    proto.__proto__ = new Proxy(proto.__proto__, {
        has(target, prop) {
            log("FAIL: proxy saw " + prop);
        }
    });

} catch (e) {
    log("Caught: " + e);
}

function log(s)
{
    document.getElementById("console").appendChild(document.createTextNode(s + "\n"));
}
</script>

<script>var undefined_variable</script>