HTML Scraping AJAX Paging Table in PHP

I am trying to scrape a webpage that has an AJAX paging html table. I can get the first page of the table fine but I want to be able to get every single page in the table. Here is an example of an ajax paging table.

This how I am currently scraping the first page:

   <?php
    include_once('simple_html_dom.php');

    class JobPosting {
        var $Id;
        var $RequistionNumber;
        var $Title;
        var $JobCategory;
        var $EmployeeClassification;
        var $PartTime; 
        var $City;
        var $Location;     
    }

    function GetJobPostings($filter)
    {
        $html = file_get_html('https://rn21.ultipro.com/SQU1001/jobboard/listjobs.aspx');

        $JobPostings = array();
        $headerFlag = true;

        foreach($html->find('table.GridTable > tbody > tr') as $job) 
        {
            if($headerFlag == true)
            {
               $headerFlag = false; 
            }
            else
            {
                $count = 0;
                $jobposting = new JobPosting;

                foreach($job->find('td') as $property)
                {
                    switch ($count) {
                        case 0:
                            $jobposting->Id = $property->find('a')[0]->href;
                            $jobposting->RequistionNumber = $property->plaintext;
                            break;
                        case 1:
                            $jobposting->Title = $property->plaintext;
                            break;
                        case 2:
                            $jobposting->JobCategory = $property->plaintext;
                            break;
                        case 3:
                            $jobposting->EmployeeClassification = $property->plaintext;
                            break;
                        case 4:
                            $jobposting->PartTime = $property->plaintext;
                            break;
                        case 5:
                            $jobposting->City = $property->plaintext;
                            break;
                        case 6:
                            $jobposting->Location = $property->plaintext;
                            break;
                    }       
                    $count++;
                }

                if($jobposting->Company == $filter )
                {
                    array_push($JobPostings, $jobposting);
                }      
            }

        }

        return $JobPostings;
    }
    ?>

How can I get all the job postings from this website?

Here is the request from fiddler for the example:

Answer

At the end of the POST content, search for __PreparedPXDO and change the value of __PageNumber:

__VIEWSTATE=%2FwEPDwUENTM4MWRk8%2BV34Sl40tIYo214geiPudK8q8E%3D&__VIEWSTATEGENERATOR=0906FCBB&__EVENTVALIDATION=%2FwEWDQLRjdiVBQLZmLPIBwLRmtKmBwLJvYapAwKduOGWBgKC9qGSBQL99cOUCAK2xqmfDQKj96rgDQLLvLGTDwLArLTaDQKD%2BaqJAQLUpr%2FLD8lqfch4SOH0EsNlMYgxMFw%2FPlV6&__PXPOSTBACK=1&__PXLBN=&__PXLBV=&__PXDO=&__Keywords=&__RecordsPerPage=&__PreparedPXDO=*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&__PageNumber=  ->HERE<-  &__Next=+%3E+

---

You can easily create a loop to scrap all available pages, i.e.:

<?php
$num = 1;
while($num < 5){
$postFields = "__VIEWSTATE=%2FwEPDwUENTM4MWRk8%2BV34Sl40tIYo214geiPudK8q8E%3D&__VIEWSTATEGENERATOR=0906FCBB&__EVENTVALIDATION=%2FwEWDQLRjdiVBQLZmLPIBwLRmtKmBwLJvYapAwKduOGWBgKC9qGSBQL99cOUCAK2xqmfDQKj96rgDQLLvLGTDwLArLTaDQKD%2BaqJAQLUpr%2FLD8lqfch4SOH0EsNlMYgxMFw%2FPlV6&__PXPOSTBACK=1&__PXLBN=&__PXLBV=&__PXDO=&__Keywords=&__RecordsPerPage=&__PreparedPXDO=*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&__PageNumber=$num&__Next=+%3E+";

$curlHeaders = array(
"Host: rn21.ultipro.com",
"User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:46.0) Gecko/20100101 Firefox/46.0",
"Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
"Accept-Language: en-US,en;q=0.5",
"Accept-Encoding: gzip, deflate, br",
"Referer: https://rn21.ultipro.com/SQU1001/jobboard/listjobs.aspx?Page=Browse",
"Cookie: __jbsrcid=*86EE06D72F666815; ASP.NET_SessionId=3vvj3v55gadspcyklbfg2gip; BIGipServerrn21.ultipro.com_http_pool=366258698.20480.0000",
"Connection: keep-alive",
"Content-Type: application/x-www-form-urlencoded",
"Content-Length: " . strlen($postFields)
);

$url = "https://rn21.ultipro.com/SQU1001/jobboard/listjobs.aspx?Page=Browse";

$ch = curl_init();
curl_setopt($ch,CURLOPT_URL, $url);
curl_setopt($ch,CURLOPT_FOLLOWLOCATION, 1);
curl_setopt($ch,CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch,CURLOPT_HTTPHEADER, $curlHeaders);
curl_setopt($ch,CURLOPT_POSTFIELDS, $postFields);
$result = curl_exec($ch);
curl_close($ch);

echo $result;

$num++;
}
?>

---

The trick is to make a first post (next page button) using a normal browser and sniff the post content using live http headers for firefox, or similar, and emulate it after using curl.
I’ve tested the code above and I was able to retrieve all job posts on the website.