<input type="checkbox" name="id[]" value="12">
<input type="checkbox" name="id[]" value="123">
<input type="checkbox" name="id[]" value="17">
<input type="checkbox" name="id[]" value="12233">
<div id="testing"></div>
<script>
var inps=$("input[name='id[]']");
inps.change(function(){
var ololo='';
inps.each(function(){if($(this).is(':checked')){ololo+=$(this).val()+'; ';}});
$('#testing').html(ololo);
});
</script>