kartik select2 ajax
echo $form->field($model, 'city')->widget(Select2::classname(), [
'data' => $data,
'options' => ['multiple'=>true, 'placeholder' => 'Search for a city ...'],
'pluginOptions' => [
'allowClear' => true,
'minimumInputLength' => 3,
'language' => [
'errorLoading' => new JsExpression("function () { return 'Waiting for results...'; }"),
],
'ajax' => [
'url' => $url,
'dataType' => 'json',
'data' => new JsExpression('function(params) { return {q:params.term}; }')
],
'escapeMarkup' => new JsExpression('function (markup) { return markup; }'),
'templateResult' => new JsExpression('function(city) { return city.text; }'),
'templateSelection' => new JsExpression('function (city) { return city.text; }'),
],
]);