$(document).ready(function () {
    $('body').append('<div id="modalBackground" class="modalBackground" style="position:absolute;z-index:9000;top:0;left:0"></div>');
});
function AtivarModal(botaoId, modalId) {
    var maskHeight = $(document).height();
    var maskWidth = $(document).width();
    var winH = $(window).height();
    var winW = $(window).width();
    $(botaoId).click(function (e) {
        e.preventDefault();
        $("#modalBackground").css({ 'width': maskWidth, 'height': maskHeight });
        $("#modalBackground").fadeIn(1000).fadeTo("slow", 0.8);
        $(modalId).css('top', ((winH - $(modalId).height()) / 2) + $(document).scrollTop());
        $(modalId).css('left', (winW - $(modalId).width()) / 2);
        $(modalId).fadeIn(2000);
    });
    $("#modalBackground, " + modalId + " .close").click(function (e) {
        e.preventDefault();
        $(modalId +", #modalBackground").hide();
    });
    $(document).scroll(function () {
        $(modalId).css('top', ((winH - $(modalId).height()) / 2) + $(document).scrollTop());
    });
    $(document).keydown(function (e) {
        // ESCAPE key pressed
        if (e.keyCode == 27) {
            $(modalId + ", #modalBackground").hide();
        }
    });
}