<!DOCTYPE html>

<html>

<head>

    <title></title>

</head>

    <script>

        function onClickHander(obj){

            if(obj.checked){

                console.log("selected");

            }else{

                console.log("unselected");

            }

        }

    </script>

<body>

    <input id="checkBox" type="checkbox" onclick="onClickHander(this)"></input>

</body>

</html>