用于重置下拉列表中所选选项的按钮

I have a page with 2 select option dropdown lists and I can only use one of them each time I have to submit the selected option but if I use two and click on submit i get an error Only use one list and thats how it should work.

for example:

I have 2 drop lists like this one

if i choose both like the pic above and click on submit I get an error and the selected options are shown as the deffult option and thats what I want, but when I click on the reset button it need to reset them to the default value but nothing happens.

like this

The Options for the dropdown list is from two different arrays.

$test1 and $test2 are two different arrays

<form name="rechner" method = "POST">
<select name="one">
    <option value="" selected hidden>Choose One</option>
           <?php foreach ($test1 as $one => $value) { ?>
           <option value="<?= $value ?>" 
           <?php if ($_POST['one'] == $value) { 
                     echo 'selected="selected"';}?> ><?= $value ?>
            </option><?php
                }
            ?>
</select> 

<select name="two">
    <option value="" selected hidden>Choose one</option>
        <?php foreach ($test2 as $two => $value) { ?>
        <option value="<?= $value ?>" 
        <?php if ($_POST['two'] == $value) {
                  echo 'selected="selected"';}?> ><?= $value ?>
         </option><?php
        }
        ?>
</select> 
<input type="submit" name="calc" value="Submit" />
<input type="reset" name="reset" value="Reset">

</form>

  if ($_POST['calc'] == "Berechnen") {
    /// do something
 }

found the answer on other question Here

<script type="text/javascript">
      function resetForm($myform) {
            $myform.find('input:password, input:file, select, textarea').val('');
            $myform.find('input:radio,input:checkbox')
                        .removeAttr('checked').removeAttr('selected);
     }
</script>
<form name="rechner" method = "POST" id="myform">
           /////html code/////

<input type="button" value="Reset" onclick="resetForm($('#myform'));">
</form>