HTML

jquery select2 set value

<select id="lang" >
   <option value="1">php</option>
   <option value="2">asp</option>
   <option value="3">java</option>
</select>

<script>
	$("#lang").select2().select2('val','1');
</script>

select2 tags set value jquery

$('#mySelect').select2({
  data: ['one','two'],
  tags: true
});
$('#mySelect').val(['one','two']).trigger('change')

get select2 selected value jquery

$('#id :selected').text();

select2 set value jquery

$('#inputID').select2('data', {id: 100, a_key: 'Lorem Ipsum'});

select2 set value jquery

$('#all_contacts').select2('data', {id: '123', text: 'res_data.primary_email'});