how to cheked multiselect dropdown option?

Question

i have to multi select drop-down option and i have fetch result in ajax

$.ajax({
    type    : 'POST',
    data: {id:id},
    url     : url,
    dataType  : 'json',
    success: function(data){
        var len = data.length;
        for (var i = 0; i < len; i++) {
            var templatename1 = data[i]['templatename'];
            var fields = data[i]['fields'];
            $('#selectColumn1').val(fields);
        } 
    }
});

in var fields = data[i]['fields']; response is like a,b,c,d (comma separated)

so how to select mached record in dropdown check box select like a,b,c options?

Answer 1

 $.ajax({
    type    : 'POST',
    data: {id:id},
    url     : url,
    dataType  : 'json',
    success: function(data){
        var len = data.length;
        for (var i = 0; i < len; i++) {
            var templatename1 = data[i]['templatename'];
              if(data[i]['fields']){ 
                 var fields = data[i]['fields'].split(","); // you have to convert comma seperated string into array
              }
              $('#selectColumn1').val(fields);
              $("#selectColumn1").multiselect("refresh"); // To refresh multiselect
        }
    }
});