var set_turntime=2000;
function chk_referrer(){
    var empID = $F('referrer_sn');
	var url = './include/visitor_logs.php';
	var pars = 'sn=' + empID;
	var myAjax = new Ajax.Request(
	url,
	{
		method: 'get',
		parameters: pars
	});
}
setTimeout("chk_referrer()",set_turntime);