secret of name and id (1)

There are sevral checkbox with name 'chk'.





and you want to know how many chk boxes there.
if you're confuse id and name, you'll get different result.

1. ID
$("#chk_can").length
returns 1

2. NAME
$("input[name='chk_can']").length
returns 3

select radio button according to radio value

There're 2 radio buttons




I'd like to choose radio button and check it with jQuery accroding to DB value.
what if DB value is '10'.

>> $("input[name=FS_type]").filter('[value='10']').attr('checked',true);

It doesn't work. Any idea?