function popMessage() {
    var top = 0;
    var left = 0;
    var scrollTop = 0;

    var top;
    document.getElementById('warningMsg').style.display = 'block';
    scrollTop = (document.documentElement.scrollTop) ? document.documentElement.scrollTop : window.pageYOffset;
    if (scrollTop == undefined) { scrollTop = 0; }
    // if top is set at the clientHeight minus the division height divided by 2 plus the scrollTop it will be in the middle;
    top = ((document.documentElement.clientHeight - 126) / 2) + scrollTop;
    left = (document.documentElement.clientWidth - 290) / 2;
    // if left = the clientWidth minus the division width divided by two is the division will center.	

    document.getElementById('warningMsg').style.top = (top) + 'px';
    document.getElementById('warningMsg').style.left = (left) + 'px';

}

function closePopMessage(answer) {
    if (answer == true) {
        document.getElementById('warningMsg').style.display = 'none';
        top.location = document.location;
    }
}

var xmlhttp = null;
var timeout = 18000000;
var warning = 600000;
var dt = new Date();
var start = dt.getTime();
var warned = false;

function checkTime() {
    var d = new Date();
    var now = d.getTime();
    var timeSpent = (now - start);
    var t = '';

    var secondsLeft = ((timeout - timeSpent) / 1000);
    //alert('seconds left='+secondsLeft);
    var minutesLeft = Math.floor(secondsLeft / 60);
    //alert('minutes left='+minutesLeft);
    secondsLeft = Math.floor(secondsLeft - (minutesLeft * 60));
    var refresh;
    if (timeSpent > timeout) {
        document.location = 'sessionExpired.asp';
    }
    if (timeSpent > (timeout - warning)) {
        if (warned == false) {
            popMessage();
            warned = true;
        }
        document.getElementById('sessionStatus').innerHTML = 'Your session will expire in ' + minutesLeft + ' minutes: ' + secondsLeft + ' seconds';
        // setTimeout('getAnswer',100); confirm('Your session is about to expire.\nRefresh the page.\nYou have in '+minutesLeft+' minutes: '+secondsLeft+' seconds remaining.\n\nClick OK to refresh your session or click Cancel to ignore.');
    } else {
        //alert('session has been alive for:'+(timeSpent/1000)+' seconds\nYou have in '+minutesLeft+' minutes: '+secondsLeft+' seconds remaining.');
    document.getElementById('sessionStatus').innerHTML = 'Your session will expire in ' + minutesLeft + ' minutes: ' + secondsLeft + ' seconds';
    }
    setTimeout('checkTime()', 1000);
}