JSFiddle - React, Tailwind, and code Playground

HTML

<li class="odd"><input type="checkbox"  class="forminput" name="VD12" checked="checked" value="5">
<a href="#">example 1</a></li>

<li class="odd"><input type="checkbox"  class="forminput" name="VD12" checked="checked" value="1">
<a href="#">example 1</a></li>

<li class="odd"><input type="checkbox"  class="forminput" name="VD12" checked="checked" value="2">
<a href="#">example 1</a></li>

<li class="odd"><input type="checkbox"  class="forminput" name="VD12" checked="checked" value="3">
<a href="#">example 2</a></li>

<li class="odd"><input type="checkbox"  class="forminput" name="VD12" checked="checked" value="4">
<a href="#">example 3</a></li>

<li>
<input type="checkbox" id="checkall" name="checkall" checked="checked"> 
<label for="checkall">check all</label>
<input type="button" value="copy the checked link" class="button">
</li>

JavaScript

$(".button").click( function () {
           var selectedCheckboxValue = "";
    $('input.forminput:checked').each(function() { 
              
                  selectedCheckboxValue += $(this).val() + ", ";
              
          });
          alert(selectedCheckboxValue);
});