JSFiddle - React, Tailwind, and code Playground

HTML

<select id="email" multiple data-rel="chosen" class="input-xlarge" name="email[]">
 <option value="[email protected]">[email protected]</option><option value="[email protected]">[email protected]</option>
<option value="[email protected]">[email protected]</option>
</select>
<br>
The selected would be in a input text below.
<br>
<input id="emailsend" class="emailKirim" name="emailKirim">

CSS

#email {
    
    width: 60%;
}

#emailsend {
    
    margin-top: 30px;
    height: 60px;
    width: 90%;
}

JavaScript

$("#email").on('change', function() {
           var thisval = $(this).val() + '';
           var myarr = thisval.split(',');
           var newval = '';
           myarr.forEach(function(i,v) {
               newval += i + ' , ';
              
           });
           newval = newval.slice(0, newval.length - 3);
           $("#emailsend").val(newval);
   
      });