PHP - 加载所有动态内容后获取页面内容

我尝试获取此页面的源代码：https://www.assetstore.unity3d.com/en/
我想为一个小项目解析右侧的"最高付费"框，但是当我使用file_get_contents或以下代码时，我没有得到正确的源代码。

$cookie = tmpfile();
$userAgent = 'Mozilla/5.0 (Windows NT 6.2; WOW64) AppleWebKit/537.31 (KHTML, like Gecko) Chrome/26.0.1410.64 Safari/537.31' ;
$ch = curl_init('https://www.assetstore.unity3d.com/en/');
$options = array(
    CURLOPT_CONNECTTIMEOUT => 20 ,
    CURLOPT_USERAGENT => $userAgent,
    CURLOPT_AUTOREFERER => true,
    CURLOPT_FOLLOWLOCATION => true,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_COOKIEFILE => $cookie,
    CURLOPT_COOKIEJAR => $cookie ,
    CURLOPT_SSL_VERIFYPEER => 0 ,
    CURLOPT_SSL_VERIFYHOST => 0 ,
    CURLOPT_TIMEOUT => 10
);
curl_setopt_array($ch, $options);
$kl = curl_exec($ch);
curl_close($ch);
echo $kl;
?>

返回：

<div id="assetstore">
    <section id="content-panels">
        <div id="adminarea"></div>
        <div id="downloadarea" class="outer-content">
            <div class="flex">
                <div id="packagelistUI"></div>
                <div id="packagelist"></div>
            </div>
        </div>
        <div id="contentarea">
            <div id="content" class="main">
                <section id="mainContent"></section>
            </div>
        </div>
    </section>
</div>

但是最高付费框位于"主要内容"部分。我将如何访问此代码？

解决感谢Pramod，这是我现在的代码：

<?php
// An example of using php-webdriver.
require_once('lib/__init__.php');
// start Firefox with 5 second timeout
$host = 'http://localhost:4444/wd/hub'; // this is the default
$capabilities = DesiredCapabilities::firefox();
$driver = RemoteWebDriver::create($host, $capabilities, 5000);
// navigate to 'http://docs.seleniumhq.org/'
$driver->get('https://www.assetstore.unity3d.com/en/');
// adding cookie
$driver->manage()->deleteAllCookies();
$driver->manage()->addCookie(array(
  'name' => 'cookie_name',
  'value' => 'cookie_value',
));
$cookies = $driver->manage()->getCookies();
// wait at most 10 seconds until at least one result is shown
$driver->wait(10)->until(
  WebDriverExpectedCondition::presenceOfAllElementsLocatedBy(
    WebDriverBy::className('top-list')
  )
);
$sString = $driver->getPageSource();
// close the Firefox
$driver->quit();
print_r($sString);