W3c is the body that tries to standardize this stuff, they generate the rules, then programmers create their rendering engine to interpret Those people regulations. - Free support on installation, configuration, and customization as per retail outlet requirements, one example is, new hook addition in your retail store Other : https://crossbookmark.com/story19264080/prestashop-popup-on-exit-page-on-browser-tab-close-event-things-to-know-before-you-buy