Safari 10 on macOS Sierra turns off Flash by default

Like Google and Microsoft, Apple will be deemphasizing Adobe Flash in its first-party web browser. The next version of Safari, Safari 10, which will be part of macOS Sierra when it comes out for everyone in the fall, will have Flash turned off by default. People will have to turn on Flash for each website they visit and grant it permission to work just once or every time.

The news was not part of the macOS Sierra segment of the keynote of Apple’s WWDC developer conference on Monday. Instead, word of the changes arrived in a post on the WebKit blog, where Apple has cross-posted updates on the Safari Technology Preview browser in recent months.

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“By default, Safari no longer tells websites that common plugins are installed,” Apple software engineer Ricky Mondello wrote in today’s blog post. (Hat tip to MacRumors for reporting on the news.) “It does this by not including information about Flash, Java, Silverlight, and QuickTime in navigator.plugins and navigator.mimeTypes. This convinces websites with both plugin and HTML5-based media implementations to use their HTML5 implementation.

“Of these plugins, the most widely-used is Flash. Most websites that detect that Flash isn’t available, but don’t have an HTML5 fallback, display a ‘Flash isn’t installed’ message with a link to download Flash from Adobe. If a user clicks on one of those links, Safari will inform them that the plugin is already installed and offer to activate it just one time or every time the website is visited. The default option is to activate it only once. We have similar handling for the other common plugins.”

Something similar will happen when there’s a Flash element embedded on a website: People will have to click a “Click to use” button and then choose whether to have Flash work just once for that site or every time.

“Whenever a user enables a plug-in on a website, it’ll remain enabled as long as the user regularly visits the website and the website still uses the plug-in,” Mondello wrote. “More specifically, Safari expires a user’s request to activate a plug-in on a particular website after it hasn’t seen that plug-in used on that site for a little over a month.”

Google and Microsoft have also been moving to promote HTML5 over Flash on websites, on Chrome and Edge respectively, in order to provide better performance, cut down on the potential for security issues, and simplify Web development.

In Safari 10 it will be possible to refresh a page with all plugins activated with an option in Safari’s View menu. The security section of Safari’s preferences window will let users control which plugins get activated.

Developers can prepare for the change by installing the beta version of macOS Sierra, and Apple will come out with betas of Safari 10 for OS X Yosemite and El Capitan “later this summer,” Mondello wrote.