• Added el.insertAdjacentElement() and el.insertAdjacentText().
• Added the firing of a cancelable reset event to form.reset(). (epfremmer)
• Added the type, value, and defaultValue properties to <output> elements, including their form reset behavior. (epfremmer)
• Added the outputEl.htmlFor property.
• Fixed the performance of parsing large text nodes, particularly noticeable for large inline <style> or <script> elements. This regressed in v11.6.0. To learn more, see V8 issue #6730.
• Fixed the style property on <a> and <area> elements. This regressed in v13.0.0.
• Fixed node.isConnected to not always return false for nodes inside a shadow tree. (pmdartus)
• Fixed <button type="reset"> and <input type="reset"> elements to actually perform a form reset when clicked, instead of doing nothing. (epfremmer)
• Fixed el.setCustomValidity() for <output> and <fieldset>.
• Fixed activation behavior when dispatching bubbling click events, so that for example calling el.click() on the child of a submit button element will submit the form.
• Fixed our XML parsing code to ignore text outside the root element, instead of treating it as an error. (lddubeau)
• Fixed XML serialization when elements had an unknown prefix.
• Fixed radio button group name matching to be case-sensitive, per a spec update.
• Fixed focus/blur events to be composed.
• Fixed mediaElement.duration to default to NaN.
• Fixed olEl.start to default to 1.
• Fixed using XMLHttpRequest against non-existant file: URLs to treat that as a network error, instead of crashing. (pascalbayer) Note that in the future we may completely disable XMLHttpRequest usage against file: URLs to follow the browser security model.
• Fixed document.title in SVG documents.
• Fixed titleElement.text to return the child text content, instead of being the same as titleElement.innerHTML.
• Fixed <textarea>s to properly account for child CDATA section nodes changing.
• Fixed the value of Element.prototype[Symbol.unscopables].