function keepSession()
{
	var aktiv = window.setInterval("doRequest()", 120000);

}
function doRequest()
{
	var myAjax = new Ajax.Request(
				"sessionKeeper.php", 
				{
					method: 'get'
					,onComplete: showResponse
				});

}
function showResponse(originalRequest)
{
//	alert(originalRequest.responseText)
}