Why am I getting 400 Bad Request?

Question

Parsing

Hello! Not strong in parsing, so I ask for advice from experienced professionals. When a page of a site is requested by the curl, I get and display its content. There is a button on the site, when you click on it, the list of products is dynamically loaded in 20 pieces, I tracked it in the chrome debugger and found that there are some parameters that are most likely related to loading content with Ajax.

Do I understand correctly that these are post-parameters? If so, then I pass them to the request

$post = array(
'act' => 'data-more',
'page' => '3', 
'eng' => '44536', 
'sys' => 'guest', 
);

$html = request('http://www.site.ru', $post);
echo $html;

but I get a 400 Bad Request error. If instead of $post send null , then I get the page I'm looking for but with 20 products. How can I get a page with at least 40 products? Where is the mistake?

Answer 1

Do I understand correctly that these are post-parameters? If so, then I pass them to the request

1. On the basis of what did you understand this?
2. what does the request function do?
3. 400 Bad Request

Answer 2

Thanks to everyone for the answers, the issue has already been resolved, fixed the entry 'Accept: application/json, text/javascript, */*; q=0.01',