How to retireve data stored in select2 dropdown?

I am using laravel 5 and select2 dropdown for selecting various tags similar to stackoverflow tag field.

So once a number of tags are selected i want to retrieve them in the form of array and use it in laravel 5's controller to validate and store.

Also if user clicks edit post i want to add all the tags in the dropdown from the database so user can easily make changes.

1) So mainly i want to know how can i retrieve data in form of array from select2

2) populate the select2 with data when user clicks edit How do i achieve these 2 functionality ?

<select multiple="multiple"
    id="class_select"
    class="form-control"
    name="tag_select"
    value=""
    required
    >

    <option value="">PHP</option>
    <option value="">C++</option>
</select>

<script>
    $( document ).ready(function() {

        $("#tag_select").select2();

        $('#showbola').click(function(){
            $("#tag_select").text();
        });
    });
</script>

via Chebli Mohamed