PHP select menu starting from current year - php

Question

I am using Bootstrap and PHP. The formmail works however the last option value (the year) in the code below prints the value from the previous option value (the day). I am not sure where I went wrong.
Values post to email:
Serve by Month.: 1
Serve by Day.: 2
Serve by Year.: 2 (year is the same as day)
<select id="Serve_by_Month" name="Serve_by_Month" required>
<option value="">Month*</option>
<?for($xx=1;$xx<13;$xx++){?>
<option value="<?=$xx?>"<?if($xx==$exp_mo)echo " selected";?>>
<?=sprintf("%02d",$xx)?>
</option>
<?}?>
</select>
<br class="hidden-lg">
<select id="Serve_by_Day" name="Serve_by_Day" required>
<option value="">Day*</option>
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
<option value="5">5</option>
<option value="6">6</option>
<option value="7">7</option>
<option value="8">8</option>
<option value="9">9</option>
<option value="10">10</option>
<option value="11">11</option>
<option value="12">12</option>
<option value="13">13</option>
<option value="14">14</option>
<option value="15">15</option>
<option value="16">16</option>
<option value="17">17</option>
<option value="18">18</option>
<option value="19">19</option>
<option value="20">20</option>
<option value="21">21</option>
<option value="22">22</option>
<option value="23">23</option>
<option value="24">24</option>
<option value="25">25</option>
<option value="26">26</option>
<option value="27">27</option>
<option value="28">28</option>
<option value="29">29</option>
<option value="30">30</option>
<option value="31">31</option>
</select>
<select id="Serve_by_Year" name="Serve_by_Year" required>
<option value="">Year*</option>
<?
$year = date("Y");
$yearto = date("Y")+10;
while ($year <= $yearto)
{
echo "<option value='".$year."'>".$year."</option>";
$year++;
}
?>
</select>

Answer 1

It's been a long time since I did any php, but could this issue have something to do with date("Y") returning a string and not an int?
Try changing the $year assignment to
$year = intval(date("Y"));
$yearto = $year+10;

Answer 2

Try this, it should solve your problem
<?php
if(isset($_POST['submit-form'])){
$selectedMonth = $_POST['Serve_by_Month']; //This will give you the month
$selectedDay = $_POST['Serve_by_Day']; //This will give you the day
$selectedYear = $_POST['Serve_by_Year']; //This will give you the year
echo 'date: '.$selectedMonth.'-'.$selectedDay.'-'.$selectedYear;
echo '<br>';
}
?>
<form method="post">
<select id="Serve_by_Month" name="Serve_by_Month" required>
<option value="">Month*</option>
<?php
for($i=1;$i<13;$i++){
$selected = $i==$exp_mo ? 'selected' : '';
?>
<option value="<?=$i?>" <?=$selected?>>
<?=sprintf("%02d",$i)?>
</option>
<?php } ?>
</select>
<br class="hidden-lg">
<select id="Serve_by_Day" name="Serve_by_Day" required>
<option value="">Day*</option>
<?php
for($i = 1; $i <= 31; $i++){ ?>
<option value="<?=$i?>"><?=$i?></option>
<?php }
?>
</select>
<select id="Serve_by_Year" name="Serve_by_Year" required>
<option value="">Year*</option>
<?php
for($i = date('Y'); $i <= date('Y')+10; $i++){?>
<option value="<?=$i?>"><?=$i?></option>
<?php }
?>
</select>
<input type="submit" name="submit-form"/>
</form>