Javascript, PHP, Ruby functionsI assume you are very familiar with declaring functions in any of the languages above, if not, you should not be reading this. Let’s begin with a simple function to send email in these languages:// PHP or Javascriptdo_send_email (recipient, cc, subject, body);// Rubydo_send_email (recipient, cc, subject, body)So it’s clear by looking at the function’s signature that it takes 4 parameters and they could be optional, depends on your implementation. Even if you missed one parameter, in most cases it is fine, no complain, no fatal error.First enc...