JavaScript: The Definitive Guide, Fourth Edition

Name

Sample Entry — how to read core JavaScript reference pages

Title and Short Description

Every reference entry begins with a four-part title block like that above. The entries are alphabetized by title. The short description, shown below the title, gives you a quick summary of the item documented in the entry; it can help you quickly decide if you’re interested in reading the rest of the page.

Availability

The availability information is shown in the upper-right corner of the title block. This information tells you which version of Netscape’s JavaScript interpreter and Microsoft’s JScript interpreter the item (class, method, or property) was introduced in. If the item has been standardized in ECMAScript, it tells you which version of the standard introduced it. You can assume that anything available in one version of JavaScript is also available in later versions. Note, however, that if this section says the item is deprecated it may be removed in the future and you should avoid using it.

Inherits from/Overrides

If a class inherits from a superclass or a method overrides a method in a superclass, that information is shown in the lower-right corner of the title block.

As described in Chapter 8, JavaScript classes can inherit properties and methods from other classes. For example, the String class inherits from Object, and the RangeError class inherits from Error, which in turn inherits from Object. When you see this inheritance information, you may also want to look up the listed ...