<!DOCTYPE html>
<script>
function submitForm()
{
    document.forms[0].submit();
}

function fillForm(data)
{
    document.getElementsByName("foo")[0].value = data;
}

function getFormData()
{
    return document.getElementsByName("foo")[0].value;
}

document.addEventListener("visibilitychange", function(event) {
    // Send a signal to the test controller via alert.
    alert('visibilitychange');
});

</script>
<form method=post>
<input name=foo value="Some unimportant data">
<input type=submit>
</form>