chromium/src/third_party/blink/web_tests/fast/js/vardecl-preserve-vardecl.html

<p>This test verifies that var declarations in different evaluation units don't stomp each other.</p>
<pre id="console"></pre>

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

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

<script>
var x = 1;
y = 1;
</script>

<script>
var x;
var y;

if (x == 1)
    log("PASS: x should be 1 and is.");
else
    log("FAIL: x should be 1 but instead is " + x + ".");

if (y == 1)
    log("PASS: y should be 1 and is.");
else
    log("FAIL: y should be 1 but instead is " + y + ".");
</script>