1. AbortController & AbortSignal

    Controller object that allows you to abort one or more DOM requests made with the Fetch API.

  2. ChaCha20-Poly1305 cipher suites for TLS

    A set of cipher suites used in Transport Layer Security (TLS) protocol, using ChaCha20 for symmetric encryption and Poly1305 for authentication.

  3. COLR/CPAL(v0) Font Formats

    The COLR table adds support for multi-colored glyphs in a manner that integrates with the rasterizers of existing text engines. COLRv0 only supports pure colors, does not support gradients, transformations and various blending modes.

  4. COLR/CPAL(v1) Font Formats

    COLRv1 is an improved version of COLRv0, this is also part of the OpenType specification. COLRv1 supports additional graphic capabilities. In addition to solid colors, gradient fills can be used, as well as more complex fills using other graphic operations, including affine transformations and various blending modes.

  5. Basic console logging functions

    Method of outputting data to the browser's console, intended for development purposes.

  6. console.time and console.timeEnd

    Functions for measuring performance

  7. CSS caret-color

    The `caret-color` property allows the color to be set of the caret (blinking text insertion pointer) in an editable text area.

  8. CSS print-color-adjust

    The `print-color-adjust` (or `-webkit-print-color-adjust` as prefixed in WebKit/Blink browsers) property is a CSS extension that can be used to force printing of background colors and images.

  9. CSS color() function

    The CSS `color()` function allows the browser to display colors in any color space, such as the P3 color space which can display colors outside of the default sRGB color space.

  10. Media Queries: resolution feature

    Allows a media query to be set based on the device pixels used per CSS unit. While the standard uses `min`/`max-resolution` for this, some browsers support the older non-standard `device-pixel-ratio` media query.

  11. CSS overflow-anchor (Scroll Anchoring)

    Changes in DOM elements above the visible region of a scrolling box can result in the page moving while the user is in the middle of consuming the content. By default, the value of `overflow-anchor` is `auto`, it can mitigate this jarring user experience by keeping track of the position of an anchor node and adjusting the scroll offset accordingly

  12. CSS overscroll-behavior

    CSS property to control the behavior when the scroll position of a scroll container reaches the edge of the scrollport.

  13. ::placeholder CSS pseudo-element

    The ::placeholder pseudo-element represents placeholder text in an input field: text that represents the input and provides a hint to the user on how to fill out the form. For example, a date-input field might have the placeholder text `YYYY-MM-DD` to clarify that numeric dates are to be entered in year-month-day order.

  14. :placeholder-shown CSS pseudo-class

    Input elements can sometimes show placeholder text as a hint to the user on what to type in. See, for example, the placeholder attribute in HTML5. The :placeholder-shown pseudo-class matches an input element that is showing such placeholder text.

  15. #rrggbbaa hex color notation

    The CSS Color Module Level 4 defines new 4 & 8 character hex notation for color to include the opacity level.

  16. CSS Scroll-behavior

    Method of specifying the scrolling behavior for a scrolling box, when scrolling happens due to navigation or CSSOM scrolling APIs.

  17. CSS @scroll-timeline

    CSS property that allows animations to be driven by a container's scroll position

  18. CSS scrollbar styling

    Methods of styling scrollbars' color and width.

  19. CSS Scroll Snap

    CSS technique that allows customizable scrolling experiences like pagination of carousels by setting defined snap positions.

  20. CSS3 Colors

    Method of describing colors using Hue, Saturation and Lightness (hsl()) rather than just RGB, as well as allowing alpha-transparency with rgba() and hsla().

  21. CSS currentColor value

    A CSS value that will apply the existing `color` value to other properties like `background-color`, etc.

  22. Document Policy

    A mechanism that allows developers to set certain rules and policies for a given site. The rules can change default browser behaviour, block certain features or set limits on resource usage. Document Policy is useful both for security and performance, and is similar to [Permissions Policy](/permissions-policy).

  23. document.scrollingElement

    `document.scrollingElement` refers to the element that scrolls the document.

  24. Scroll methods on elements (scroll, scrollTo, scrollBy)

    Methods to change the scroll position of an element. Similar to setting `scrollTop` & `scrollLeft` properties, but also allows options to be passed to define the scroll behavior.

  25. Feature Policy

    This specification defines a mechanism that allows developers to selectively enable and disable use of various browser features and APIs. Feature Policy is deprecated and has been replaced with [Permissions Policy](/permissions-policy) and [Document Policy](/document-policy).

  26. Geolocation

    Method of informing a website of the user's geographical location

  27. High Resolution Time API

    Method to provide the current time in sub-millisecond resolution and such that it is not subject to system clock skew or adjustments. Called using `performance.now()`

  28. Color input type

    Form field allowing the user to select a color.

  29. input placeholder attribute

    Method of setting placeholder text for text-like input fields, to suggest the expected inserted information.

  30. theme-color Meta Tag

    Meta tag to define a suggested color that browsers should use to customize the display of the page or of the surrounding user interface. The meta tag overrides any theme-color set in the web app manifest.

  31. CSS3 Multiple column layout

    Method of flowing information in multiple columns

  32. Reversed attribute of ordered lists

    This attribute makes an ordered list number its items in descending order (large to small), instead of ascending order (small to large; the default). The order that the list items are displayed in is not affected.

  33. Permissions Policy

    A security mechanism that allows developers to explicitly enable or disable various powerful browser features for a given site. Similar to [Document Policy](/document-policy).

  34. prefers-color-scheme media query

    Media query to detect if the user has set their system to use a light or dark color theme.

  35. Referrer Policy

    A policy that controls how much information is shared through the HTTP referrer header. Helps to protect user privacy.

  36. Custom protocol handling

    Method of allowing a webpage to handle a given protocol using `navigator.registerProtocolHandler`. This allows certain URLs to be opened by a given web application, for example `mailto:` addresses can be opened by a webmail client.

  37. scrollIntoView

    The `Element.scrollIntoView()` method scrolls the current element into the visible area of the browser window. Parameters can be provided to set the position inside the visible area as well as whether scrolling should be instant or smooth.

  38. Element.scrollIntoViewIfNeeded()

    If the element is fully within the visible area of the viewport, it does nothing. Otherwise, the element is scrolled into view. A proprietary variant of the standard `Element.scrollIntoView()` method.

  39. SPDY protocol

    Networking protocol for low-latency transport of content over the web. Superseded by HTTP version 2.

  40. URL Scroll-To-Text Fragment

    URL fragment that defines a piece of text to be scrolled into view and highlighted.

  41. hashchangeevent api: oldurl

  42. idbversionchangeevent api: oldversion

  43. mutationrecord api: oldvalue

  44. pushsubscriptionchangeevent api: oldsubscription

  45. storageevent api: oldvalue

  46. html element: ol

  47. html element: ol: compact

  48. html element: ol: reversed

  49. html element: ol: start

  50. html element: ol: type