Safari is the best way to see the sites on iPhone, iPad, and Mac. Safari Technology Preview gives you an early look at upcoming web technologies in OS X and iOS including the latest layout technologies, visual effects, and developer tools so you can provide input on how they are implemented and deliver a best-in-class user experience on all Apple devices.
Here's some highlighted features...
Easy to update. You can update Safari Technology Preview right from the Mac App Store. Updates occur every few weeks and include the most recent additions and improvements to WebKit.
Access powerful developer tools. Use the latest version of the powerful Web Inspector and Responsive Design Mode to modify, debug, and optimize your websites.
Provide feedback. Use Bug Reporter to send feedback directly to Apple about issues and enhancement requests. Simply select Report an Issue from the Help menu in Safari Technology Preview.
Run side-by-side with Safari. Safari Technology Preview is a standalone app that works side-by-side with the current version of Safari, so you can continue to use and reference the current release.
Surf seamlessly with iCloud. Safari Technology Preview works with iCloud, so you can access your latest Safari Favorites, bookmarks, and Reading List.
You can download Safari Technology Preview from the link below...