JavaScript Fundamentals
JavaScript is an interpreted scripting language that is object based and full featured.
JavaScript is the programming language most frequently supported by web browsers. JavaScript code is embedded into the HTML of web pages. The code can interact with the Document Object Model (DOM), which represents HTML and browser objects. This enables web pages to implement dynamic features such as animations, transitions, text color changes, and text effects.
JavaScript that runs in a web browser is called client-side JavaScript because it runs on a client computer instead of on a web server.
The JavaScript language uses a syntax similar to that of C, and supports structured constructs, such as if...else, for, and do...while. Braces ({}) are used to delimit statement blocks. The language supports various data types, including String, Number, Boolean, Object, and Array. It includes support for enhanced date features, trigonometric functions, and regular expressions.
JavaScript uses prototypes instead of classes. You can define an object by creating a constructor function.
JavaScript is a loosely typed language, which means you do not declare the data types of variables explicitly. In many cases JavaScript performs conversions automatically when they are needed. For example, if you add a number to an item that consists of text (a string), the number is converted to text.
JavaScript for Internet Explorer 9 is the Microsoft implementation of the ECMAScript 5th Edition (ES5) language specification. JavaScript for Internet Explorer 9 also provides additional features that are not included in the Ecma Standards.