input-named-action-overrides-action-attribute.html

<body onload="test()">
<form action="/">
   <input type=hidden name="action" value="">
</form>
<p>This tests that access to a form's element named "action" overrides the "action" property on a form element (from the HTML DOM).</p>
<p>If the test passes, the next paragraph will say "Test Passed".</p>
<p id="result"></p>
<script>
    function test() {
        if (window.testRunner)
            testRunner.dumpAsText();
        document.forms[0].action.value = "Passed";
        document.getElementById("result").innerText = "Test " + (document.forms[0].action.value ? document.forms[0].action.value : "Failed");
    }
</script>

chromium/third_party/blink/web_tests/fast/forms/input-named-action-overrides-action-attribute.html