The HTMLFormElement interface provides methods to create and modify <form> elements. document.forms - returns an array of HTMLFormElement objects referencing all forms on the page. document.forms[index] - returns an HTMLFormElement object referencing the form at the specified index. document.forms['id'] - returns an HTMLFormElement object referencing the form with the specified id. document.forms['name'] - returns an HTMLFormElement object referencing the form with the specified id.
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 HTMLMediaElement interface adds to HTMLElement the properties and methods needed to support basic media-related capabilities that are common to audio and video. The HTMLVideoElement and HTMLAudioElement elements both inherit this interface.
The DataTransferItem object represents one drag data item. During a drag operation, each drag event has a dataTransfer property which contains a list of drag data items. Each item in the list is a DataTransferItem object.
The read-only DataTransferItem.type property returns the type (format) of the DataTransferItem object representing the drag data item. The type is a Unicode string generally given by a MIME type, although a MIME type is not required.
The DataTransferItemList object is a list of DataTransferItem objects representing items being dragged. During a drag operation, each DragEvent has a dataTransfer property and that property is a DataTransferItemList.
The DataTransferItemList.add() method creates a new DataTransferItem using the specified data and adds it to the drag data list. The item may be a File or a string of a given type. If the item is successfully added to the list, the newly-created DataTransferItem object is returned.