Попробуй так.

[code]
////////HTML
<form action="/test.php" method="post" id="form">
<textarea name="text"></textarea>
</form>
<a href="#" onclick="return submit();">Кнопочка</a>

////////JS
<script type="text/javascript">
function submit(){
document.getElementById('form').submit();
}
</script>

[/code]