[bes]

<form>
	<input type=text name=textField size=45> 
	<input type="button" value="Ответ">
</form>

<script>
window.onload = function () {
	document.forms[0].children[1].onclick = function () {
		var text = document.forms[0].textField.value;
		if (text == 'ha') {
			location.href = 'http://javascript.ru';
		} else {
			alert('ответ неверный');
		}
	}
}
</script>