how can i put checkbox value on textarea?

1. Air Conditioning
 
2. Easy Transfer/ Connection  
3. Less Waiting Time  
4. Less Walk to/ From Stops  

5. Fares are standarize  
6. Clean Vehicles  
7. Clean Terminals/ station  

         <input type="checkbox" class="chkbox" value="8"> 8. Assured Seat &nbsp;
          <br>
           <br>
           <input type="checkbox" class="chkbox" value="9"> 9. Terminal/Station/Vehicle Safety &nbsp;
     <input type="checkbox" class="chkbox" value="10"> 10. With Trip Schedule &nbsp;
       <input type="checkbox" class="chkbox" value="11"> 11. With Wifi &nbsp;
         <input type="checkbox" class="chkbox" value="12"> 12. With TV &nbsp;
          <br>
           <br>
           <input type="checkbox" class="chkbox" value="13"> 13. Connectivity with Others Routes &nbsp;
     <input type="checkbox" class="chkbox" value="14"> 14. Comfortable seats/ not cramped &nbsp;
       <input type="checkbox" class="chkbox" value="15"> 15. Schedule Information/ Maps at terminal/ station/ stops &nbsp;
       <br>
           <br>
         <input type="checkbox" class="chkbox" value="16"> 16. With CCTV/Security in Vehicles/ Terminals/ Stops &nbsp;
          
           <input type="checkbox" class="chkbox" value="17"> 17. Informative directional signs at terminals/ stations transfer points

 

18. Availability of convenience store/toilet/amenities in
terminal/station  

19. Well Lighted especially at night/ no blind spot  

         <input type="checkbox" class="chkbox" value="20"> 20. Professional and courteous driver/staff &nbsp;
         <br>
           <br>
           Others &nbsp; <input type="text" class="chkbox" value=""> <br>  <br>
   
                   <div class="input-group">
                       
                       <div class="input-group-prepend">
                       
                       </div>
    
   <textarea class="form-control" placeholder=""  id="selected_text" name="selected_text" rows="8"></textarea>
                     </div>
                     <!-- /.input group -->
                   </div>
   
   <script>
   
   $(document).ready(function(){
     $('.chkbox').click(function(){
   var text ="";
   $('.chkbox:checked').each(function(){
     text += $(this).val()+ ',';
   });
   text=text.substring(0,text.length-1);
   $('#selected_text').val(text);
   
     });
   });
   </script>