Button Pilih Satuan

<div class="input-group">
    <div class="input-group-control">
        <input type="text" class="form-control obat_satuan" id="satuan" name="satuan" placeholder="Satuan" onkeydown="checktxtbox()" readonly>
        <label for="form_control_1">Satuan</label>
    </div>
        <span class="input-group-btn btn-right">
            <button class="btn blue-madison pilih_satuan" type="button" data-toggle="modal" data-target="#pilihsatuan" title="Pilih Satuan" id="butn" name="butn" disabled>
                <i class="fa fa-search"></i>
            </button>
        </span>
</div>