At the end of the Development Phase, the QA person will review the site. They will use a link checker as well as look at each page to determine if the design has been accurately implemented and there are no technical errors. They will also use tools such as Browser Stack that displays the site on different browsers e.g. Internet Explorer 9, Chrome on a Mac.
Make sure to review the ‘browser spec’ during the Definition phase that is included in the Project Plan. This lists all of the browsers and screen dimensions that the site will be tested for.