Mozilla Firefox browser to block 'not essential' Adobe Flash content

The partial Flash block, scheduled for the Firefox update on August 2, will be applied to content that users cannot see, like so-called "supercookies" planted by ISPs and similar entities for user tracking. Initially, the Mozilla blog post announcing the block notes that plugins that are on the Firefox block list all have functionality that can be duplicated in HTML 5.

Later in the year, Mozilla will also further block Flash plugins intended to measure advertising effectiveness, beyond just supercookies. Mozilla will roll out a new HTML 5 API at that time for website coders to duplicate the features of the Flash plugin that will be blocked from loading.

Starting in 2017, Firefox users will have to approve any Flash content loading, regardless of source. Mozilla recommends that websites that rely on Flash or Silverlight for media presentation or games adopt HTML 5 alternatives to Flash as soon as possible.

Mozilla works with Adobe to secure and improve Flash, and has for some time. However, in the blog post outlining the timeline for blocks, the company claims that "Plug-ins often introduce stability, performance, and security issues for browsers" adding that "this is not a trade-off users should have to accept."

As Adobe updates its Flash plugin, or as security issues are discovered with the plugin, Apple deprecates the old ones, and remotely disables them from working in Safari. Additionally, Safari version 6.1 and newer has security settings that can be configured by the user to always allow, completely block, or ask the user if a specific website is allowed to execute Flash content.