select previously selected dropdown value on form self submit - php

Question

I have a 'this year' dropdown with a form attached. I then select one of the years, like say 2016. When I click the submit button I want the page to be reloaded while the value in the dropdown stays at 2016 (the one that was previously selected).
How can I do that? Here's my form:
<form class="form" method="POST" id="myID" name="myName">
<label id="year" name="year">YEARS</label>
<select name="year" id="year" class="form-control">
<option value="0" selected disabled="">CHOOSE YEAR</option>
<?php foreach($year as $rows){?>
<option value="<?php echo $rows->years?>"><?php echo $rows->years?>
</option>
<?php }?>
</select>
<button id="filter_button" style="margin-top: 26px" name="filter_button"
type="submit" class="for btn btn-info">Show</button>
</form>

Answer 1

You should use the value from $_POST to set the selected as default. Below is the updated code:
<form class="form" method="POST" id="myID" name="myName">
<label id="year" name="year">YEARS</label>
<select name="year" id="year" class="form-control">
<option value="0" selected disabled="">CHOOSE YEAR</option>
<?php foreach($year as $rows){
$isSelected = (isset($_POST['year']) && ($_POST['year'] == $rows->years)) ? 'selected' : '';
?>
<option <?php echo $isSelected; ?> value="<?php echo $rows->years?>"><?php echo $rows->years?>
</option>
<?php }?>
</select>
<button id="filter_button" style="margin-top: 26px" name="filter_button"
type="submit" class="for btn btn-info">Show</button>
</form>