title: Change "for" attribute when specific input is selected
body: <p>I got multiple lightboxes but only one link </p>
  
  <pre><code>    &lt;label class="btn" for="modal-2"&gt;more...&lt;/label&gt;
  </code></pre>
  
  <p>I want the "for" attribute to change to "modal-3" when the input with the id "id3" is selected, and to "modal-4" when "id4" is selected etc.
  when i change the "for" attribute manually, it works but i dont want to change my code all the time just to open another modal :D</p>
  
  <pre><code>                   $(document).ready(function() {
  
                        $("#id3").on("change", function() {
                          if (document.getElementById("id3").checked) {
                            $('.btn').attr('for', 'modal-4');
                          }
                        });
                      });
  </code></pre>
  
  <p>I got this already and this won't work. In my html file there's another script tag for the header of my website. Does this affect my other script?  </p>