onload modal popup bootstrap 3 code example
Example: bootstrap pop modal from another modal
// Hide current modal before opening new one
$("#idModal").modal('hide');
$("#idModal2").modal() // or .modal("show");
// show 1st modal again after closing 2nd modal
$("#idModal2").on('hidden.bs.modal', () => $("#idModal").modal('show'))
// using hide.bs.modal might cause modal to stop scrolling!!!