$('#nmberone').click(function() {
    $('#mainCoantiner, #formBg').removeClass('mystyleSec');
  $('#mainCoantiner, #formBg').removeClass('mystylethird');
  event.stopPropagation();
});



$('#nmbertwo').click(function() {
   $('#mainCoantiner, #formBg').removeClass('mystylethird');
    $('#mainCoantiner, #formBg').addClass('mystyleSec');
  event.stopPropagation();
});


$('#numberthree').click(function() {
   /* $('#catbox').removeClass('cat2');*/
    $('#mainCoantiner, #formBg').addClass('mystylethird');
  event.stopPropagation();
});