ivt32,
http://learn.javascript.ru/forms-methods
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
</head>
<body>
<a href="#" id="show-button">Отправить сообщение</a>
<form id="xform" action="/" onsubmit="return false">
<input name="text" type="text">
</form>
<script>
document.getElementById('show-button').onclick = function() {
document.getElementById('xform').submit();
};
</script>
</body>
</html>