Execute JS server-site to generate hash for xhr

Question

There is a scrapebot-proof form. The login & password inputs have the obfuscated name attribute:

<input id="login-username" name="r0pUsRqARu" value=""
 type="text" class="form-control" placeholder="Login">

Based on those inputs (incl. login and password values) and hidden char input field the hash value is generated client-side by js functionality (md5.js).

$("#btn-login").click(function(){
     var ser = $( "#loginform" ).serialize();  
     $.post("/post.php",ser+"&hash="+md5(ser),function(){
         location.replace("/logged.php");});
     });

The form is serialized and is sent as POST xhr (ajax) to post.php for logging in (see the code above).

I want to write php script to automatically log in through the form.

No problem with getting the form on server, fetching name attributes, pasting login/password values and requesting by POST xhr to /post.php with serialized string.

cV2sD3JzH2=login&3JX2zJ7QlC=password&char=%C2%AA&hash=...

Yet, since the hash is generated client-side by js (by md5.js), I can't generate hash server side by php... What's the way out?

Some thoughts:

1. Transform md5.js into a server-side script and execute it to produce hash. How?
2. Use AngularJS (or similar JS framework on server) to run md5.js on server to produce hash. Disclaimer: I'm not familiar with AngularJS.

Update

Sorry, I've presumsiously thought I could fetch the obfuscated name attribute values and char input value server-side. Yet, as RamRaider mentioned, without javascript enabled they are named *email* and *password* and no hidden char input is in the html when javascript is disabled. So, when fetching content with php cUrl (no js server-side), I have a clean form without hidden char input and unobfuscated name values, see it below (removed styling):

<form id="loginform" method="post" action="/post.php">
  <input id="login-username" type="text"  name="email" value="" >                   
  <input id="login-password" type="password" name="password" >
  <a id="btn-login" href="#" class="btn btn-success">Login  </a>
</form>

Again JS tricks that are not avail at server-side. How can I fix it?

I was seraching for JS inserting somewhere new attribute values, but in vain. It should be smth. like the following:

$('login-form').attr('name', <new value>); 

Answer 1

It is not obvious where the md5.js that's being used there comes from or where the doc is for it. As such, you have these options:

1. You can test it to see if it generates the same results as PHP's MD5 function on a bunch of different inputs.
2. You can attempt to find the author of that md5.js and ask them.
3. You can just port it to PHP (it's just math) and be sure you have the same algorithm.
4. You can study the source of both implementations to see if you can conclude whether it's implementing the exact same algorithm.

I'd suggest you start with the first option since that's the easiest way to immediately tell whether they might be the same algorithm or not.