Bootstrap modal popup close on button (type=submit) post back asp.net c#

Question

bootstrap modal popup on post back event of button (type=submit) it's close automatically.asp.net c# web form. (type=submit)

Solutions that don't work:

1. I could not get it to work with an Update Panel.

2. Can't reopen like javascript thorough again modal popup show. Because I am opening modal up from different page.

    function OpenModal() {
       var strUrl = "page.aspx";
       $('.modal-body').load(strUrl, '', function () {
           $('#myModal').modal();
       });
   }