There are several properties you can look at in order to determine the width and height of elements, and it can be tricky to determine which is the right one for your needs. This article is designed to help you make that decision.  Note that all these properties are read-only.  If you want to set the width and height of an element, use  width and height; or, the overriding min-width and max-width, and min-height and max-height properties.
There are a number of web technologies that store data of one kind or another on the client-side (i.e. on your local disk.) The process by which the browser works out how much space to allocate to web data storage and what to delete when that limit is reached is not simple, and differs between browsers. This article attempts to explain how this all works.
The url read-only property of the Client interface returns the URL of the current service worker client.
The IDBEnvironment interface of the IndexedDB API contains the indexedDB property, which provides access to IndexedDB functionality. It is the top level IndexedDB interface implemented by the window and Worker objects.