Answers for "instead of mdoel backgroudn is scroll css\"

javascript disable scrolling on body

document.body.style.overflow = 'hidden';

prevent body from scrolling when a modal is opened

$('#adminModal').modal().on('shown', function(){
    $('body').css('overflow', 'hidden');
}).on('hidden', function(){
    $('body').css('overflow', 'auto');
})