The WindowBase64.atob() function decodes a string of data which has been encoded using base-64 encoding. You can use the window.btoa() method to encode and transmit data which may otherwise cause communication problems, then transmit it and use the window.atob() method to decode the data again. For example, you can encode, transmit, and decode control characters such as ASCII values 0 through 31.
Elements in HTML have attributes; these are additional values that configure the elements or adjust their behavior in various ways to meet the criteria the users want.
The accesskey global attribute provides a hint for generating a keyboard shortcut for the current element. This attribute consists of a space-separated list of characters (one single Unicode code point). The browser uses the first one that exists on the computer keyboard layout.
The contenteditable global attribute is an enumerated attribute indicating if the element should be editable by the user. If so, the browser modifies its widget to allow editing. The attribute must take one of the following values:
The data-* global attributes form a class of attributes, called custom data attributes, allows proprietary information to be exchanged between the HTML and its DOM representation that may be used by scripts. All such custom data are available via the HTMLElement interface of the element the attribute is set on. The HTMLElement.dataset property gives access to them.
The * may be replaced by any name following the production rule of xml names with the following restrictions:
dir
The dir global attribute is an enumerated attribute indicates the directionality of the element's text. It can have the following values:
The hidden global attribute is a Boolean attribute indicating that the element is not yet, or is no longer, relevant. For example, it can be used to hide elements of the page that can't be used until the login process has been completed. Browsers won't render elements with the hidden attribute set.
Note: The maximum value for tabIndex should not exceed 32767 per W3C section 17.11.1
The title global attribute contains a text representing advisory information related to the element it belongs to. Such information can typically, but not necessarily, be presented to the user as a tooltip. Here are some typical uses of this attribute:
The function keyword can be used to define a legacy generator function inside an expression. To make the function a legacy generator, the function body should contain at least one yield expression.
Just like pseudo-classes, pseudo-elements are added to selectors but instead of describing a special state, they allow you to style certain parts of a document. For example, the ::first-line pseudo-element targets only  the first line of an element specified by the selector.
The symbols() function allows counter styles to be defined inline, directly as the value of the CSS property. Unlike styles defines with @counter-style, these styles are anonymous. The symbols() function doesn't have all the capabilities and options of the @counter-style at-rule, but is useful in cases such as when the style is used only once and you don't need all the the options provided by @counter-style.
The AbstractWorker interface of the Web Workers API abstracts properties and methods common to all kind of workers, being Worker or SharedWorker.
ArrayBufferView is a helper type representing any of the following JavaScript TypedArray types:
A Boolean value indicating whether or not the device's battery is currently being charged.
Indicates the amount of time, in seconds, that remain until the battery is fully charged.
Indicates the amount of time, in seconds, that remains until the battery is fully discharged.
Indicates the current battery charge level as a value between 0.0 and 1.0.
The Blob.size property returns the size in bytes of the Blob or a File.