Надо не по HTTP
Mixed Content: The page at 'https://eyeinc.ru/' was loaded over HTTPS, but requested an insecure script 'cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery...'. This request has been blocked; the content must be served over HTTPS.
Mixed Content: The page at 'https://eyeinc.ru/' was loaded over HTTPS, but requested an insecure script 'http://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js'. This request has been blocked; the content must be served over HTTPS.
$_POST["_6_checkbox_name"][0] // Как то так, будет равно = Работа 6
$_POST["_7_checkbox_name"][0] // Как то так, будет равно = Работа 7
Нет варианта события, от сервера до клиента вообще может не быть связи по протоколу http, технически .... (ключ "от сервера")