Returns an array-like object of all child elements which have all of the given class names. When called on the document object, the complete document is searched, including the root node. You may also call getElementsByClassName() on any element; it will return only elements which are descendants of the specified root element with the given class names.
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.
HTML Drag and Drop interfaces enable applications to use drag and drop features in Firefox and other browsers. For example, with these features, the user can select draggable elements with a mouse, drag the elements to a droppable element, and drop those elements by releasing the mouse button. A translucent representation of the draggable elements follows the mouse pointer during the drag operation.
The HTMLContentElement.select property reflects the select attribute. It is a DOMString containing a space-separated list of CSS selectors that select the content to insert in place of the <content> element.