HandleAlertBoxPHPSeleniumAjaxCalljQuery.php

<?php
/*before this is all your code that is doing things to the browser and perhaps submitting some data via ajax*/
//Lets make the webdriver wait for the ajax call
$webdriverWait = new WebDriverWait($driver, 10);
$webdriverWait->until(
  //pass in our closure
  function($driver)
  {
    echo 'loop...';
    try
    {
      //Wait for jQuery to be done processing ajax request
      $result = (0 === count($driver->executeScript("return jQuery.active == 0")));
    } 
    catch (\Exception $ex) {
      //catch an exception when execScript is called when an alert box is open.  
      //the Facebook driver will automatically handle closing the alert box
      //return true so we can break out of the loop, and 
      $result = true;
    }
    return $result;
  }
);
/*continue with your script*/