var popUpLink = "";

function openPopUp() {

    var popUpWindow = $('popup_content');
	
    var popUpAllowed = allowPopUp();

    if (popUpAllowed && popUpWindow != null) {
        

        var viewportDimensions = document.viewport.getDimensions();
        var viewportScrollOffsets = document.viewport.getScrollOffsets();

        var popUpDimensions = popUpWindow.getDimensions();

        var left = (viewportDimensions.width - popUpDimensions.width) / 2;
        var top = viewportScrollOffsets.top + (viewportDimensions.height - popUpDimensions.height) / 2;

        popUpWindow.setStyle({ top: top + 'px', left: left + 'px' });

        var link = $$('#popup_content a')[0].readAttribute('href');

        if (link != '') {
            popUpLink = $$('#popup_content a')[0].href;
        }

        $$('#popup_content a')[0].href = "javascript:return false;";
        popUpWindow.onclick = function() { closePopUp() }

        popUpWindow.setStyle({ display: 'block' });
    }
}

function closePopUp() {
    $('popup_content').setStyle({ display: 'none' });

    var now = new Date();
    var month = now.getMonth() + 1;
    var year = now.getFullYear();
    var day = now.getDate();

    var expires = new Date(year, month, day + 2);

    document.cookie = 'lastPopUpShown=' + month + '/' + day + '/' + year + ';path=/;expires=' + expires.toGMTString ();

    if (popUpLink != '')
        window.location = popUpLink;
}

function allowPopUp() {
    var now = new Date();
    var month = now.getMonth() + 1;
    var year = now.getFullYear();
    var day = now.getDate();
    var today = new Date(year, month - 1, day);

    var cookieDateString = readCookie('lastPopUpShown');
//alert(cookieDateString );
    var cookieDate = new Date(cookieDateString);

    return cookieDate < today;
}

function readCookie(name) {
    var nameEQ = name + "=";
    var ca = document.cookie.split(';');
    for (var i = 0; i < ca.length; i++) {
        var c = ca[i];
        while (c.charAt(0) == ' ') c = c.substring(1, c.length);
        if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length, c.length);
    }
    return null;
}


function addLoadEvent(func) {
    var oldonload = window.onload;
    if (typeof window.onload != 'function') {
        window.onload = func;
    } else {
        window.onload = function() {
            if (oldonload) {
                oldonload();
            }
            func();
        }
    }
}

addLoadEvent(openPopUp);