JSFiddle - React, Tailwind, and code Playground

HTML

<input type="checkbox" class="blah" id="blah123" />
<input type="checkbox" class="blah" id="blah456" />
<input type="checkbox" class="blah" id="blah789" />
<input type="checkbox" class="blah" id="blahxyzmoo" />
 
<a id="x" href="#">run</a>
<div id="out"></div>

JavaScript

function GetSelectedCheckboxIds(className) {
    var ln = className.length;
    var result = false;
    var res = $('.' + className + ':checked').map(function() {
        result = true;
        return this.id.substring(ln);
    }).get();
    alert(result);
    return res;
}

$('#x').click(function(e) {
    e.preventDefault();
    $('#out').html(GetSelectedCheckboxIds('blah').join('; '));
});