JSFiddle - React, Tailwind, and code Playground

by kneidels

HTML

Initial date: 
<input type="date" class="" name="firstdate" id="firstdate">
<br />
<input type="button" class="btn btn-inverse" value="Set" id="setall"><br>
<br>
 Output dates: <input type="text" id="CheckPostDate1" class="datepicker" value="">
  <input type="text" id="CheckPostDate2" class="datepicker" value="">
   <input type="text" id="CheckPostDate3" class="datepicker" value="">
    <input type="text" id="CheckPostDate4" class="datepicker" value="">
     <input type="text" id="CheckPostDate5" class="datepicker" value="">
      <input type="text" id="CheckPostDate6" class="datepicker" value="">
       <input type="text" id="CheckPostDate7" class="datepicker" value="">
        <input type="text" id="CheckPostDate8" class="datepicker" value="">
         <input type="text" id="CheckPostDate9" class="datepicker" value="">
          <input type="text" id="CheckPostDate10" class="datepicker" value="">
           <input type="text" id="CheckPostDate11" class="datepicker" value="">
            <input type="text" id="CheckPostDate12" class="datepicker" value="">
             <input type="text" id="CheckPostDate13" class="datepicker" value="">
              <input type="text" id="CheckPostDate14" class="datepicker" value="">
               <input type="text" id="CheckPostDate15" class="datepicker" value="">

JavaScript

$(document).ready(function(){
						 
			$("#setall").click(function(){

                
                var firstdate = new Date($("#firstdate").val());
				var dayOnly = firstdate.getDate();
				var monthOnly = firstdate.getMonth();
				var yearOnly = firstdate.getFullYear();
                if (dayOnly > 30) {dayOnly = 30}
                var currentMonth = monthOnly;
                
               // for 1 to 15: CheckPostDate 
				for (let i = 1; i < 16; i++) {
                    currentMonth = currentMonth+i-1;
                    if (currentMonth == 13 ){
                        currentMonth = 1;
                        yearOnly = yearOnly + 1;
                    }
                    
                    var currentdate = new Date(yearOnly, currentMonth, dayOnly);
                    //alert(increment);
                    $("#CheckPostDate"+i).val(currentdate);  
                }
                         
                         
			});
		
		});