The trimLeft() and trimRight() methods of strings return a new string with whitespace removed from the beginning or end of the string. They're aliases for trimStart() and trimEnd().

The setPosition() and setOrientation() methods of the AudioListener API set the virtual position and orientation of a person relative to sound sources, to spatialize audio in a Web Audio context.

The __proto__ property of objects partially exposes the prototype of an object.

The __defineGetter__() and __defineSetter__() methods of objects bind a function to a property, which is called on setting or reading the property.

The escape() and unescape() built-in Javascript methods encode and unencode strings using percent encoding, where certain characters are replaced by hexadecimal escape sequences.

The getYear() and setYear() methods of Date objects get and set the year as an offset to 1900.

JavaScript built-in methods such as, String.bold() and String.italics(), wrap strings in (often historic) HTML.

The compile() method of RegExp objects recompiles an existing regular expression object using a new pattern and flags.

The toGMTString() method of Date objects is an alias to the toUTCString() method.

The window.external.AddSearchProvider() and window.external.IsSearchProviderInstalled() do nothing. Historically, they added external search providers to the browser.

The RegExp object has several static properties to access the input and results of the most-recent regular expression match.

The callee property of the arguments variable in a non-strict function body's local scope is the function that arguments belongs to.

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.

The page-break-before, page-break-inside, and page-break-after CSS properties are aliases to the break-before, break-inside, and break-after properties.

The device-aspect-ratio, device-height, and device-width media features describe physical properties of the displaying output device.

The rel="prefetch" attribute for the <link> HTML element is a hint to the browser that the user is likely to navigate to a resource, so the browser should preemptively fetch and cache the resource.

The window.devicePixelRatio property is the ratio of the size of one CSS pixel to the vertical size of one physical pixel on the current display device.

The wheel event fires when the user moves a mouse wheel or similar spatially rotating input device.

The WEBGL_compressed_texture_s3tc extension for WebGL 1.0 and 2.0 contexts adds S3TC compressed texture formats to compressedTexImage2D() and compressedTexSubImage2D().

The XSLTProcessor API transforms XML documents into new XML or HTML documents, using XSLT stylesheets. You can use XSLT to convert data between different XML schemas or to convert XML data into web pages or PDF documents. Also known as Extensible Stylesheet Language Transformations.

The :first, :left, and :right pseudo-classes select pages based on their position in sequence after pagination.

The beforeunload event is fired when the current window is about to be unloaded. Typically this is used to display a dialog to confirm if users really want to leave the page when there is unsaved data that would be lost.

The widows and orphans CSS properties set the minimum lines included in a text fragment created by page, column, or region breaks.

The font-variant-position CSS property sets whether to use alternate glyphs for subscript and superscript text.

The audioTracks and videoTracks APIs for media elements switch audio and video tracks during playback.

The fastSeek() method seeks an <audio> or <video> element as fast as possible, by seeking to a keyframe instead of exactly the requested time.

The playback of multiple <video> or <audio> elements can be coordinated by a MediaController instance, for example to synchronize a sign-language interpreter track with the main video track.

The WEBGL_compressed_texture_pvrtc extension for WebGL 1.0 and 2.0 contexts adds PVRTC compressed texture formats to compressedTexImage2D() and compressedTexSubImage2D().

The text-overflow CSS property with a string value sets the string representing clipped text.

The ime-mode CSS property sets the state of the input method editor for text fields.