<select project="kelas" class="form-control" name="kelas" id="kelas" onchange="" value="--">
    <option>--</option>
    <option>X TKJ 1</option>
    <option>X TKJ 2</option>
</select>
<input type="text" name="nama" id="nama" placeholder="Nama Siswa" list="ceknama" autocomplete="off" required>
    <datalist id="ceknama">
        <option value="X TKJ 1">ALEX</option>
        <option value="X TKJ 2">JOHN</option>
        <option value="X TKJ 1">SAM</option>
        <option value="X TKJ 2">ANDY</option>
    </datalist>