select2 add option
Remove the selected options :
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$('#mySelect2').val(null).trigger('change');
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Completly remove the select2 initialization :
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$('#payment_method').html('').select2({data: [{id: '', text: ''}]});
// Set the value, creating a new option if necessary
if ($('#mySelect2').find("option[value='" + data.id + "']").length) {
$('#mySelect2').val(data.id).trigger('change');
} else {
// Create a DOM Option and pre-select by default
var newOption = new Option(data.text, data.id, true, true);
// Append it to the select
$('#mySelect2').append(newOption).trigger('change');
}