Try it once. after 1 hour of research on net I found Best Solution for this Problem.
Solution:- just add script
(function () {
// hold onto the drop down menu
var dropdownMenu;
// and when you show it, move it to the body
$(window).on('show.bs.dropdown', function (e) {
// grab the menu
dropdownMenu = $(e.target).find('.dropdown-menu');
// detach it and append it to the body
$('body').append(dropdownMenu.detach());
// grab the new offset position
var eOffset = $(e.target).offset();
// make sure to place it where it would normally go (this could be improved)
dropdownMenu.css({
'display': 'block',
'top': eOffset.top + $(e.target).outerHeight(),
'left': eOffset.left
});
});
// and when you hide it, reattach the drop down, and hide it normally
$(window).on('hide.bs.dropdown', function (e) {
$(e.target).append(dropdownMenu.detach());
dropdownMenu.hide();
});
})();