javascript - 从选择框中选择月份名称和该特定月份的日期

Question

我有两个字段月份名称和日期...当我单击月份名称时我想在选择框中显示该特定月份的日期...(抱歉我的英语不好)

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我的月份名称和日期编号代码......(请为此提及任何其他简单代码)

        <form class="filterform" method="post">
            <select class="selectmonth" name="monthname">
                <option selected disabled>Select Month</option>
                <option value="1" <?php echo ($_POST['monthname'] == '1')?"selected":"" ?> >January</option>
                <option value="2" <?php echo ($_POST['monthname'] == '2')?"selected":"" ?> >February</option>
                <option value="3" <?php echo ($_POST['monthname'] == '3')?"selected":"" ?> >March</option>
                <option value="4" <?php echo ($_POST['monthname'] == '4')?"selected":"" ?> >April</option>
                <option value="5" <?php echo ($_POST['monthname'] == '5')?"selected":"" ?> >May</option>
                <option value="6" <?php echo ($_POST['monthname'] == '6')?"selected":"" ?> >June</option>
                <option value="7" <?php echo ($_POST['monthname'] == '7')?"selected":"" ?> >July</option>
                <option value="8" <?php echo ($_POST['monthname'] == '8')?"selected":"" ?> >August</option>
                <option value="9" <?php echo ($_POST['monthname'] == '9')?"selected":"" ?> >September</option>
                <option value="10" <?php echo ($_POST['monthname'] == '10')?"selected":"" ?> >October</option>
                <option value="11" <?php echo ($_POST['monthname'] == '11')?"selected":"" ?> >November</option>
                <option value="12" <?php echo ($_POST['monthname'] == '12')?"selected":"" ?> >December</option>
            </select>

            <select class="selectday" name="dayname">
                <option value="0" selected disabled>Select Day</option>
                <option value="1" <?php echo ($_POST['dayname'] == '1')?"selected":"" ?>>1</option>
                <option value="2" <?php echo ($_POST['dayname'] == '2')?"selected":"" ?>>2</option>
                <option value="3" <?php echo ($_POST['dayname'] == '3')?"selected":"" ?>>3</option>
                <option value="4" <?php echo ($_POST['dayname'] == '4')?"selected":"" ?>>4</option>
                <option value="5" <?php echo ($_POST['dayname'] == '5')?"selected":"" ?>>5</option>
                <option value="6" <?php echo ($_POST['dayname'] == '6')?"selected":"" ?>>6</option>
                <option value="7" <?php echo ($_POST['dayname'] == '7')?"selected":"" ?>>7</option>
                <option value="8" <?php echo ($_POST['dayname'] == '8')?"selected":"" ?>>8</option>
                <option value="9" <?php echo ($_POST['dayname'] == '9')?"selected":"" ?>>9</option>
                <option value="10" <?php echo ($_POST['dayname'] == '10')?"selected":"" ?>>10</option>
                <option value="11" <?php echo ($_POST['dayname'] == '11')?"selected":"" ?>>11</option>
                <option value="12" <?php echo ($_POST['dayname'] == '12')?"selected":"" ?>>12</option>
                <option value="13" <?php echo ($_POST['dayname'] == '13')?"selected":"" ?>>13</option>
                <option value="14" <?php echo ($_POST['dayname'] == '14')?"selected":"" ?>>14</option>
                <option value="15" <?php echo ($_POST['dayname'] == '15')?"selected":"" ?>>15</option>
                <option value="16" <?php echo ($_POST['dayname'] == '16')?"selected":"" ?>>16</option>
                <option value="17" <?php echo ($_POST['dayname'] == '17')?"selected":"" ?>>17</option>
                <option value="18" <?php echo ($_POST['dayname'] == '18')?"selected":"" ?>>18</option>
                <option value="19" <?php echo ($_POST['dayname'] == '19')?"selected":"" ?>>19</option>
                <option value="20" <?php echo ($_POST['dayname'] == '20')?"selected":"" ?>>20</option>
                <option value="21" <?php echo ($_POST['dayname'] == '21')?"selected":"" ?>>21</option>
                <option value="22" <?php echo ($_POST['dayname'] == '22')?"selected":"" ?>>22</option>
                <option value="23" <?php echo ($_POST['dayname'] == '23')?"selected":"" ?>>23</option>
                <option value="24" <?php echo ($_POST['dayname'] == '24')?"selected":"" ?>>24</option>
                <option value="25" <?php echo ($_POST['dayname'] == '25')?"selected":"" ?>>25</option>
                <option value="26" <?php echo ($_POST['dayname'] == '26')?"selected":"" ?>>26</option>
                <option value="27" <?php echo ($_POST['dayname'] == '27')?"selected":"" ?>>27</option>
                <option value="28" <?php echo ($_POST['dayname'] == '28')?"selected":"" ?>>28</option>
                <option value="29" <?php echo ($_POST['dayname'] == '29')?"selected":"" ?>>29</option>
                <option value="30" <?php echo ($_POST['dayname'] == '30')?"selected":"" ?>>30</option>
                <option value="31" <?php echo ($_POST['dayname'] == '31')?"selected":"" ?>>31</option>
            </select>

            <button class="showbtn" name="showbtn" type="submit">Show</button>

        </form>

Answer 1

请添加此脚本(只需复制粘贴到上面的代码下方)——注意:假定当前年份为 2017 JS FIDDLE https://jsfiddle.net/sooraz2/f4hb0b5d/

 $('.selectmonth').on('change', function(){

 var year = new Date().getFullYear();

 var month = $(this).val();


   var totalDays = new Date(year, month, 0).getDate();

  var options = '<option value="0">Select Day</option>';

  for (var i = 1; i <= totalDays; i++) {

   options+= '<option value="'+i+'">'+i+'</option>';

 }

   $('.selectday').html(options);
})


  var MonthsValue = "<?php $_POST['monthname'] ?>";
   var DayValue = "<?php $_POST['dayname'] ?>";


$(function(){

  $('.selectmonth option[value='+MonthsValue+']').prop('selected', true);
  $('.selectmonth').trigger('change')
  $('.selectday option[value='+DayValue+']').prop('selected', true);

})