Three select dropdown for school year that hides previous years

How to hide years in select dropdown if not needed. I have 3 select dropdown for school year using php code snippet. Example in the first dropdown:

    2016-2017
    2015-2016
    2014-2015
    2013-2014
    2012-2013
    2011-2012

    If i select 2012-2013, the 2nd dropdown should display:
    2016-2017
    2015-2016
    2014-2015
    2013-2014
   If i select 2014-2015, the 3rd dropdown should display:
    2016-2017
    2015-2016

Is there a possible way using php code snippet alone or do i have to use javascript? The problem is, I'd tried my code in php but no luck and the more if i use javascript since I'm not get used of it.Hope anyone could help me or give me a light on doing the next step base on my present code.

Here is my code:

<label class="control-label">SY 1:</label> 
    <select class="form-control" name="scholar_secondary_school_year" id="test" onchange="educSec(this)">
               <?php 
                $null = 'null';
                $choose = 'Choose SY';
                $Present = 'Present';
          echo '<option value='.$null.'>' .$choose.'</option>';
          echo '<option value='.$Present.'>' .$Present.'</option>';
                  for($i=date('Y');  $i > date('Y')-30; $i--){

                     $x = $i +1;
                     $y = $i;
       echo '<option value='.$y.'-'.$x.'>'.$y.'-'.$x.'</option>';
                   }?>
    </select>

    <label class="control-label">SY 2:</label> 
    <select class="form-control" name="scholar_secondary_school_year" id="test" onchange="educSec(this)">
               <?php 
                $null = 'null';
                $choose = 'Choose SY';
                $Present = 'Present';
          echo '<option value='.$null.'>' .$choose.'</option>';
          echo '<option value='.$Present.'>' .$Present.'</option>';
                  for($i=date('Y');  $i > date('Y')-30; $i--){

                     $x = $i +1;
                     $y = $i;
       echo '<option value='.$y.'-'.$x.'>'.$y.'-'.$x.'</option>';
                   }?>
    </select>

    <label class="control-label">SY 3:</label> 
    <select class="form-control" name="scholar_secondary_school_year" id="test" onchange="educSec(this)">
               <?php 
                $null = 'null';
                $choose = 'Choose SY';
                $Present = 'Present';
          echo '<option value='.$null.'>' .$choose.'</option>';
          echo '<option value='.$Present.'>' .$Present.'</option>';
                  for($i=date('Y');  $i > date('Y')-30; $i--){

                     $x = $i +1;
                     $y = $i;
       echo '<option value='.$y.'-'.$x.'>'.$y.'-'.$x.'</option>';
                   }?>
    </select>

via Chebli Mohamed