jQuery $ .post的新功能

I am wanting to make this function universal, based on button id. It currently works (somewhat) on one div, but there are multiple forms, in multiple divs on the page. Please advise...

var frm_submit_event = function(e) {
  var $this = $(this); // the button
  var frm = $('#' + selected_form_div + " form");
  console.log(frm);
  console.log(frm.serialize());

  e.preventDefault();
  $.ajax({
    type: "POST",
    url: "classes/forms/ajaxPost.php",
    data: frm.serialize(),
    dataType: "text",
    success: function($result) {
      //var obj = jQuery.parseJSON(data); if the dataType is not specified as json uncomment this

      $('#' + selected_form_div).html($result);
    },
    error: function() {
      alert('error handing here');
    }
  });
}

$(document).on("click", '.frm_submit_btn', frm_submit_event);

not sure where to go from here...

Use a switch statement, checking the button id. With each case get/build the data from the button's respected form, then pass the data into the ajax call for posting.