Scraping data from an internally-called AJAX address - php

Question

I'm trying to get leagues data from this address:
http://www.10bet.com/sports/soccer/?utm_source=shp&utm_medium=sleft&utm_campaign=soccer
In that page, if you click on "Champions League" for example, in Firebug I see an AJAX call to this address:
http://www.10bet.com/pagemethods.aspx/GetLeaguesContent
The result is a JSON object which contains matches info from that league. However, when I get that page with cURL, even when I post exact parameters, I get a bunch of JavaScript code:
$url = 'http://www.10bet.com/pagemethods.aspx/GetLeaguesContent';
$fields = array(
'BranchID' => urlencode('1') ,
'LeaguesCollection' => urlencode('10098') ,
);
$fields_string = '';
foreach($fields as $key=>$value) { $fields_string .= $key.'='.$value.'&'; }
rtrim($fields_string, '&');
$ch = curl_init();
curl_setopt($ch,CURLOPT_URL, $url);
curl_setopt($ch,CURLOPT_POST, count($fields));
curl_setopt($ch,CURLOPT_POSTFIELDS, $fields_string);
$result = curl_exec($ch);
curl_close($ch);
echo $result;

Answer 1

I took a quick look and I was able to discover the problem in about a minute. It's a missing request header. I'm not going to tell you which one but I will tell you how I discovered it so next time you can do it yourself.
First, install Charles proxy and run it. Open that page in Chrome. When the browser makes the request it will show up in Charles.
Now highlight the request in question and go down to 'Edit' on the right click menu. Just start removing the headers that you think might be the problem one at a time and re-execute the request. When it sends the javascript, you will know that the last header you removed was the one.