Advance checker script for webmails

Hello, A while ago someone developed me a simple script that verifies username and password of cPanel and posts them to the URL and checks if Valid. Now, I need the same thing to do on a number of webmails like Verizon, TalkTalk, Freenet, Shaw, Juno, etc. Just keep in mind that the function is already in place, I only need to expand it functionality. The script uses cURL to post username and password and then it catches the response and gives a result based on the response. So just to make clear, I need someone who can find the POST/GET url and the field names of these webmails.(10 of them). If further information is needed I will provide extra information. Thanks