$(window).load(function () {
    BackgroundProcess();
});

function BackgroundProcess() {
    var BackgroundName = $('.BackgroundName').val();
    $('.BodyContainer').css('background', 'url(' + $('.AjaxUrl').val() + 'Images/Background/Header' + BackgroundName + '.jpg) no-repeat 50% 0%');
    $('.Footer').css('background', 'url(' + $('.AjaxUrl').val() + 'Images/Background/Footer' + BackgroundName + '.jpg) no-repeat 50% 100%');
}