The Document.visibilityState read-only property returns the visibility of the document, that is in which context this element is now visible. It is useful to know if the document is in the background or an invisible tab, or only loaded for pre-rendering. Possible values are:
The History.length read-only property returns an Integer representing the number of elements in the session history, including the currently loaded page. For example, for a page loaded in a new tab this property returns 1.
The contentWindow property returns the Window object of an <iframe> element. You can use this Window object to access the iframe's document and its internal DOM. This attribute is read-only, but its properties can be manipulated like the global Window object.
The read-only HTMLLabelElement.control property returns a reference to the control (in the form of an object of type HTMLElement or one of its derivatives) with which the <label> element is associated, or null if the label isn't associated with a control.
The read-only HTMLLabelElement.form property returns an HTMLFormElement object which represents the form of which the label's associated control is a part, or null if there is either no associated control, or if that control isn't in a form.
The HTMLLinkElement.relList read-only property reflects the rel attribute. It is a live DOMTokenList containing the set of link types indicating the relationship between the resource represented by the <link> element and the current document.
The HTMLMediaElement.buffered read-only property returns a new TimeRanges object that indicates the ranges of the media source that the browser has buffered (if any) at the moment the buffered property is accessed.
The HTMLMediaElement.currentSrc property contains the absolute URL of the chosen media resource. This could happen, for example, if the web server selects a media file based on the resolution of the user's display. The value is an empty string if the networkState property is EMPTY.