Use this below simple code: https://jsfiddle.net/Divyesh_Patel/v7a4h3kr/7/
<input type="checkbox" id="check"> <a href="#" onclick="check()">click</a> <button onclick="check()">button</button> <script> function check() { if (document.getElementById('check').checked) { alert("checked"); } else { alert("Not checked."); } } </script>