On a webpage I have a form:

```
<form action="/SignUp.py" method="post">
    <input required type="text" name="fullName" onKeyPress="checkFinished()" autofocus>
    <input type="submit" name="submitButton" value="Sign Up" disabled>
</form>

```

and script:

```
<script>
    function checkFinished() {
        if (document.getElementsByName("fullName")[0].value.match(/. ./).length > 0) {
            document.getElementsByName("submitButton")[0].disabled = false;
        }
        else {
            document.getElementsByName("submitButton")[0].disabled = true;
        }
    }
</script>

```

If I step through the code using Firebug, I can see the execution path is correct. However, when the code hits the else clause and should be (re-)disabling `submitButton`, it does not get disabled. What am I doing wrong here?