[object Object] error

[object Object] error

I am getting [object object] error , I am trying to grab id of input and use it 

here is the codepen link : http://codepen.io/justincarb/pen/ebnHv

here is the code:


$(document).ready(function(){
  $("input[type='checkbox']").on('click', function(){
     $("input[type='checkbox']").not(this).prop('checked', false);
    });
  
  $('#button-input').on('click', function(){
    if($("input[type='checkbox']").is(':checked')){
      var Id = $("input:checked").attr('id');
      var currentId= $('#'+ Id); 
      currentId.css('background-color','red');
    }else{
        alert("Please check one Option");
      }         
  });
});

how do I use Id properly ...

Thanks 
Justin