function ShowReviewFilter() {
    MaskScreen(10005);
    var id = '#divFilter';
    var winH = $(window).height();
    var winW = $(window).width();
    var top = winH / 2 - $(id).height() / 2 + GetScrollPosition();
    var left = winW / 2 - $(id).width() / 2;
    cssObj = {
        'position': 'absolute',
        'left': left + 'px',
        'top': top + 'px',
        'display': 'block',
        'z-index': '10006',
        'border': 'black solid 1px',
        'background-color': 'white',
        'font-family': 'Verdana',
        'font-size': '10pt'
    };
    $(id).css(cssObj);
    return false;
}
function CloseReviewFilter() {
    $('#divFilter').fadeOut("fast");
    UnMaskScreen();
}
function UnMaskScreen() {
    $('#mask').fadeOut("fast");
}
function MaskScreen(zindex) {
    var maskHeight = $(document).height();
    var maskWidth = $(window).width();

    //Set height and width to mask to fill up the whole screen  
    cssObj = {
        'position': 'absolute',
        'left': '0',
        'top': '0',
        'z-index': '9000',
        'background-color': '#ccc',
        'font-family': 'Verdana',
        'font-size': '10pt',
        'width': maskWidth,
        'height': maskHeight,
        'z-index': zindex
    };
    $('#mask').css(cssObj);
    //transition effect       
    $('#mask').fadeIn(500);
    $('#mask').fadeTo("fast", 0.8);
}
function GetScrollPosition() {
    var ScrollTop = document.body.scrollTop;

    if (ScrollTop == 0) {
        if (window.pageYOffset)
            ScrollTop = window.pageYOffset;
        else
            ScrollTop = (document.body.parentElement) ? document.body.parentElement.scrollTop : 0;
    }
    return ScrollTop;
}