<div style="height: 100vh">

    <div class="container">

      <form class="container" id="x">

         <select id="select" class="mdb-select colorful-select dropdown-primary md-form"

                        name="SelectedAttributeEntryIds"

                        multiple searchable="Search here..">

                    <option value="" disabled selected>Choose your country</option>

                    <option value="1">USA</option>

                    <option value="2">Germany</option>

                    <option value="3">France</option>

                    <option value="4">Poland</option>

                    <option value="5">Japan</option>

                </select>

                <label class="mdb-main-label">Countries</label>

​

        <button type="submit" class="btn btn-success">Submit</button>

      </form>

      <h1 id="result" class="text-center"></h1>

    </div>

​

</div>