removeAttr("selected") and .attr('selected','selected') not working properly

Question

I have two select fields in my form. The first one is single-select and the other is multiple-select. Now what I want to do is select options in the multiple-select with given data depending on the chosen option in the single-select. To do this I'm firing an ajax-request when the single-select is changed:

$.ajax({
    type : 'POST',
    url : '/Controller/getMultipleSelectIds',
    data : {
        singleSelectId: singleSelectId
    },
    success : function(data) {
        var multipleSelectIds= JSON.parse(data);
        $("#multipleSelectFieldId option:selected").prop("selected", false);
        $("#multipleSelectFieldId  option").each(function()
        {
            if ($(this).val() in multipleSelectIds) {
                $(this).attr('selected','selected');
            }
        });
        $("#multipleSelectFieldId").trigger("chosen:updated");
    }
});

Lets say I have values like these in the database for the single-select-Ids:

array(
  "ssId1" => array(1,2,4,5),
  "ssId2" => array(1,3,5)
)

Now I choose the first entry in the single-select ("ssId1") and everything works fine, meaning the multiple-select gets filled just like it should (with the options with the given values 1,2,4 and 5). But when I change the single-select again to another option ("ssId2") the chosen-select only shows me option 3 (which is one value that is not one of "ssId1"). This continues until I have no more options in the chosen multiple-select.

I've checked and the options in the hidden multiple-select field are set correctly. So now the question is: Is this a bug in the chosen plugin or am I doing something wrong?

EDIT Tried to find the problem and for this made the source select visible. It seems that there is a problem with removeAttr or .prop("selected", false) or maybe even .attr('selected','selected'). When I switch between the two choices of the single-select only the option 3 is marked (blue background) but all 3 options have the selected property in the html code. I've a similar problem when I tried to select all options in a multiple-select (required) field via js/jquery in IE 11 and submitting the form IE said that there is no option chosen. What am I doing wrong?

Answer 1

Just use prop() method in all sentences, that works with dynamic attributes likeselected

See your fiddle modified with no problems:

https://jsfiddle.net/0aaxk2hz/3/

$(this).prop('selected', true); // add it
$(this).prop('selected', false); // remove it