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Originally published at Internet.comJScript .NET introduces several new features: * Compiled code * New Data Types * New Statements * New Directives * Support for New Types of Applications
This article introduces you to each of these new features and provides background information where necessary. This article assumes that you're familiar with JavaScript, JScript, or ECMAScript. You should be familiar with keywords like while, for, function, and String, and how to use them in scripts.
Compiled Code
JScript .NET is now a compiled language. To appreciate the benefit that this provides, you first need to understand how the code you write executes when it executes in an environment like Internet Explorer or in an Active Server Page (ASP).
JavaScript and JScript code executes in a host environment. When you create a Web page that contains JavaScript code and open it using a browser, like Internet Explorer, the browser acts as the host for your code. Besides displaying your Web page, the host converts your code into instructions the computer understands and then submits the converted code to your computer's processor to carry out the instructions. The host environment converts each line of the code you write into executable instructions on a just in time basis; in other words, the host and the system's processor don't have any idea of what your code will do next - they have only enough information to carry out the instructions your code provides on a line-by-line basis and only when the code is executing. The entity that performs the conversion is called an interpreter, which is usually a component of either the host environment or the host itself...
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