Safari Technology Preview release 7 now available for download

Apple has made available the seventh release of the Safari Technology Preview for developers. As with previous releases, this latest contains a slew of new tweaks and changes for developers to check out.

Here's the full breakdown of what's new in Safari Technology Preview release 7:

JavaScript

• Implemented options argument to addEventListener
• Updated JSON.stringify to correctly transform numeric array indices
• Improved the performance of Encode operations
• Addressed issues with Date setters for years outside of 1900-2100
• Fixed an issue where reusing a function name as a parameter name threw a syntax error
• Added the error argument for window.onerror event handlers
• Improved performance for accessing dictionary properties
• Updated Proxy.ownKeys to match recent changes to the spec
• Prevented RegExp unicode parsing from reading an extra character before failing
• Updated SVGs to report their memory cost to the JavaScript garbage collector
• Improved the sampling profiler to protect itself against certain forms of sampling bias that arise due to the sampling interval being in sync with some other system process
• Fixed global lexical environment variables scope for functions created using the Function constructor
• Fixed parsing super when the default parameter is an arrow function
• Added support for trailing commas in function parameters and arguments

CSS

• Added the unprefixed version of the pseudo element ::placeholder
• Fixed a crash when computing the style of a grid with only absolute-positioned children
• Fixed computing a grid container's height by accounting for the horizontal scrollbar
• Fixed placing positioned items on the implicit grid
• Fixed rendering for the text-decoration-style values: dashed and dotted
• Fixed support for using border-radius and backdrop-filter properties together
• Fixed clipping for border-radius with different width and height
• Fixed CSS reflections for elements with WebGL
• Fixed CSS reflections for elements with a backdrop-filter property
• Improved the Document's font selection lifetime in preparation for the CSS Font Loading API
• Improved memory management for CSS value parsing
• Improved font face rule handling for style change calculations
• Fixed multiple selector rule behavior for keyframe animations
• Fixed applying CSS variables correctly for writing-mode properties
• Added experimental support for spring() based CSS animations
• Changed the initial value of background-color to transparent per specs

Web APIs

• Changed CanvasRenderingContext2D.createPattern() and CanvasRenderingContext2D.putImageData() to throw the correct exception type and align with the specification
• Fixed a number of issues with Web Workers

Web Inspector

• Added ⌘T keyboard shortcut to open the New Tab tab
• Added the ability to show and hide columns in data grid tables
• Fixed an error when trying to delete nodes with children
• Added a Top Functions view for Call Trees in the JavaScript & Events timeline
• Added gaps to the overview and category graphs in the Memory timeline where discontinuities exist in the recording
• Improved the performance of DOM tree views
• Fixed filtering to apply to new records added to the data grid
• Improved snapshot comparisons to always compare the later snapshot to the earlier snapshot no matter what order they were selected
• Improved performance when processing many DOM.attributeModified messages
• Fixed the 60fps guideline for the Rendering Frames timeline when switching timeline modes
• Included the exception stack when showing internal errors in Web Inspector
• Added ⌘P keyboard shortcut for quick open
• Removed Text → Content subsection from the Visual Styles Sidebar when not necessary
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• Fixed elements in the Elements tab losing focus when selected by the up or down key
• Enabled combining diacritic marks in input fields in Web Inspector Enabled combining diacritic marks in input fields in Web Inspector

Media

• Prevented double-painting the outline of a replaced video element
• Properly prevented video.play() for video.src="file" with audio user gesture restrictions in place
• Prevented showing the caption menu if the video has no selectable text or audio tracks
• Improved performance of HTMLMediaElement.prototype.canPlayType that was accounting for 250–750ms first loading theverge.com
• Fixed inline media controls to show PiP and fullscreen buttons

Rendering

• Fixed a repaint issue with vertical text in an out-of-flow container
• Show text in a placeholder font while downloading the specified font
• Fixed rendering an SVG in the correct vertical position when no vertical padding is applied, and in the correct horizontal position when no horizontal padding is applied
• Fixed blending of inline SVG elements with transparency layers
• Fixed display of hairline borders on 3x displays
• Prevented flickering and rendering artifacts when resizing the web view
• Fixed logic to trigger new layout after changing canvas height immediately after page load

Bug Fixes

• Fixed an issue where Find on Page would show too many matches
• Exposed static text if form label text only contains static text
• Added Origin header for CORS requests on preloaded cross-origin resources
• Added support for the upgrade-insecure-requests (UIR) directive of Content Security Policy
• Added proper element focus and caret destination for keyboard users activating a fragment URL
• Increased disk cache capacity when there is lots of free space
• Prevented hangs during synchronous XHR requests if a network session doesn't exist
• Fixed the response for a POST request on a blob resource to return a "network error" instead of HTTP 500 response
• Restricted HTTP/0.9 responses to default ports and cancelled HTTP/0.9 resource loads if the document was loaded with another HTTP protocol
• Fixed parsing URLs containing tabs or newlines
• Fixed cookie validation in private browsing
• Provided memory cache support for the Vary header

If you're a developer interested in experimenting with new changes to the browser before they hit the general release, you can download the latest release directly from Apple.