Device-bound session credentials is a protocol to request proof of possession of a private key. Regularly confirming key possession can help protect against cookie theft.

The digital credentials API issues and requests digital credentials, such as driver's licenses or ID cards, with the browser or operating system. Digital credentials extend the navigator.credentials credential management API.

The window.getDigitalGoodsService API connects to stores or billing services for in-app products and subscriptions.

A document's bgColor, fgColor, alinkColor, linkColor, and vlinkColor properties get and set the background, foreground, active link, link, and visited link colors of that document.

The document picture-in-picture API creates an always-on-top window from arbitrary HTML content.

The EXT_disjoint_timer_query extension for WebGL 1.0 contexts measures the duration of a set of GL commands, without stalling the rendering pipeline.

The EXT_float_blend extension for WebGL 1.0 and 2.0 contexts adds 32-bit floating-point components to blending and draw buffers.

The EXT_frag_depth extension for WebGL 1.0 and 2.0 contexts adds setting the depth value of a fragment from within the fragment shader.

The EXT_texture_compression_bptc extension for WebGL 1.0 and 2.0 contexts adds the BPTC compressed texture formats to compressedTexImage2D() and compressedTexSubImage2D().

The EXT_texture_norm16 extension to WebGL 2.0 contexts adds 16 bit signed normalized and unsigned normalized fixed-point texture, renderbuffer, and texture buffer formats.

TLS 1.3 sessions may be resumed more quickly by sending so-called early data to servers before the TLS handshake has finished. Also known as zero round-trip time resumption or 0-RTT.

The EditContext API allows you to build rich text editors that support advanced text input, such as Input Method Editor (IME) composition, an emoji picker, or other platform-specific editing UI.

The restrictTo() method on screen capture media tracks limits capture to a specific element, excluding content which might occlude the element itself, such as video conferencing controls.

The element performance entry and the PerformanceElementTiming API measures the time to render elements that have the elementtiming attribute.

The startViewTransition() method of an Element object starts a view transition that affects only that element's DOM tree. You can use this to run separate elements' transitions concurrently.

The Error.isError() static method checks whether a value is an Error object.

The using and await using declarations and the dispose and asyncDispose symbols manage the lifecycle of resources such as file handles and streams. The DisposableStack and AsyncDisposableStack objects can group, dispose, and coordinate dependencies between multiple disposable resources.

The EyeDropper API opens an eyedropper tool, a color picker that allows users to select a color from their screen.

The Feature-Policy response header sets whether a policy-controlled feature, such as an API, may be used in a document. Not to be confused with permissions policy.

The IdentityCredential API delegates authentication to a third-party identity provider, instead of using third-party cookies. Also known as FedCM.

The FederatedCredential API represents the details required to authenticate a user using a third-party identity provider. Not to be confused with federated credential management (FedCM).

The Request.formData() and Response.formData() methods read a request or response body and return a FormData promise. You can use it to access the fields of a form submission.

The Sec-Fetch-Dest, Sec-Fetch-Mode, Sec-Fetch-Site, and Sec-Fetch-User HTTP headers provide extra information about the way a request was made, to help servers reject certain kinds of malicious requests.

The fetch() method and Request() constructor accept a ReadableStream object as the request's body option, to stream upload data to the server.

The file_handlers web app manifest member registers an installed web app as a handler for files with specific file extensions or MIME types.

The showOpenFilePicker(), showDirectoryPicker(), and showSaveFilePicker() methods request access to files and directories on the user's device and returns a handle for reading and writing to them.

The ascent-override, descent-override, and line-gap-override descriptors adjust the display of a font declared in an @font-face statement. This can help make fallback fonts look the same size.

The toolname, tooldescription, and toolautosubmit HTML form element attributes register actions that can be called by in-browser AI agents or browser extensions. Also known as declarative WebMCP.

The fullscreen API makes a specific element fill the whole screen and hides most browser UI.

The caller and arguments properties of a non-strict mode Function object are the function that called it and the arguments it was called with. Not to be confused with the arguments variable in a function body's local scope.