Question

<form method="post" id="formFinish2"> 
    <input type="checkbox" name="finish" /> 
    <input type="hidden" name="id" class="finishId" value="2" /> 
</form> 

<script type="text/javascript"> 
    $(":checkbox[name='finish']").click(function() { 
        id = $(this).closest('input.finishId').val(); 
        alert(id); 
        $("#formFinish".id).submit(); 
    }); 
</script> 

Alerts me undefined. I would like it to alert me 2, which is coming from the input that has the class finishId, next to the checkbox you clicked on.

Answer 1

It’s because closest only searches DOM upward. In other words, closest starts searching by father element, then grandfather element, etc.

You should use siblings instead.

$(this).siblings('input.finishId').val();