How do I set a selected value to a drop down jquery/JQM

I'm generating a dynamic drop down and trying to apply a value to it based on what's retrieved from another asynchronous call. At first I thought the value wasn't being applied because the dropdown wasn't fully created at the time I was setting the value...drop down is being created like so..and then applying the values to the form with the "GetOrderCallSucceeded" (a bunch of $('').val(value) calls, they work for everything accept for the dropdown)

function getEorder(id) {
var ReasonTypesPromise = makeAJAXcall("{}", "GetReasonTypes");
var getMedOrderPromise = makeAJAXcall("{'eMedOrderId':'" + id + "'}", "GetMedicalOrder");

  $.when(ReasonTypesPromise, getMedOrderPromise).done(function (reasons, formdata) {
      var items = JSON.parse(reasons.d), lr = JSON.parse(formdata.d);

      for(var i in items) {
        $('#ReasonForLifeVestDropdown')
        .append($("<option></option>")
        .attr("value", items[i].ReasonTypeID)
        .text(items[i].Name));

        if (items[i].ReasonTypeID == lr.ReasonTypeID) {
          $('#ReasonForLifeVestDropdown').val(lr.ReasonTypeID);
        }
      } 

      GetOrderCallSucceeded(lr);
  },
  function (error, err) {
      ajaxCallFailed(error);
  });

}

However, I was testing

$('#ReasonForLifeVestDropdown').val(lr.ReasonTypeID);
$('#ReasonForLifeVestDropdown option[value=2]').attr('selected', 'selected');

simply by triggering the jquery onclick in a button. It wasn't working either.

HTML of dropdown and Button I was using for testing.

        <div class="ui-block-a"><select id="ReasonForLifeVestDropdown"></select></div>
        <div class="ui-block-a"><button data-role="button" onclick="$('#ReasonForLifeVestDropdown option[value=2]').attr('selected', 'selected');">click</button></div>
   </div>