bootstrap 4 multi select box code example
Example: cant pass multipule select input bootstrap
<div class="col-9">
<select id="generals" name="generals" class="form-control kt-selectpicker" multiple title="Choose one of the following...">
<optgroup label="Passport">
<option value="passport_number">Number</option>
<option value="passport_date">Date of issuance</option>
<option value="passport_expired">Date of expiry</option>
<option value="passport_office">Issuing Office</option>
</optgroup>
<optgroup label="Personal">
<option value="applicant_id">Applicant Id</option>
<option value="first_name">First Name</option>
<option value="first_name">Middle Name</option>
<option value="last_name">Last Name</option>
<option value="address">Address</option>
<option value="crew_id">Crew Id</option>
<option value="email">Email</option>
<option value="mobile_number">Mobile Number</option>
</optgroup>
</select>
</div>