ajax question

[MAORBARI]

<script type="text/javascript">
<!-- 
function iimsg()
{
thisstring = message.value;
YAHOO.util.Connect.asyncRequest('POST', 'savept.php?content=' + thisstring, {
	success: msgstr.handle_ajax_response,
	failure: msgstr.handle_ajax_error,
	timeout: vB_Default_Timeout,
	scope: this
}, SESSIONURL + 'securitytoken=' + SECURITYTOKEN + '&foo=' + foo);
}

function Leaving() {
iimsg();
}
//-->
</script>

why it is dont work?
thx.