Hack with confidence.
Page pen-test-tool-lookup-ajax.php is vulnerable to at least the following:
Javascript Object Notation (JSON) Injection: This page uses JSON to pass data which is later parsed and incorporated into the page. Because the output is not properly encoded, it is possible to carefully craft an injection which will add extra data into the JSON without breaking the JSON syntax. This extra data will be executed by the browser once the data is incorporated into the page.