Answer 1

@Stenly

Nice idea!

Such a code, would have to manipulate html and javascript.

Probably a cross platform software or plugin.

Answer 2

with PowerShell you can use a com-object (internet explorer) so in c# you can use it also with using the automation library. but plain C will hard. I would recommend to you change the starting point. but good luck.

Answer 3

POST method. With Java I've automated my ISP login.