Website content is more than just visible text. The translator needs to take into account URLs, keywords, metatags and, more generally, all the invisible content trawled by search engines in order to position the website in search results. For this reason, SEO and other factors must be kept in mind.
Furthermore, many different file formats are used: HTML, PHP, XML, PO… and the translations must be delivered in the same format, respecting the tags in all these markup languages. Finally, when a website is translated, final testing is paramount. To do this, when validating the final texts, the translator checks that all the translated text is correctly formatted and that usability standards are met.