JavaScript for BASIC Programmers

AppStudio's BASIC is modelled on Microsoft's Visual BASIC. It runs on other operating system by translating the BASIC to JavaScript, a language which is supported on all platforms.

JavaScript is a powerful and flexible programming language. It's the standard programming language of the web. It's also the subject of Atwood's Law: "Any application that can be written in JavaScript, will eventually be written in JavaScript."

When we designed our Translator, we were pleased to discover that almost everything in BASIC had a direct equivalent in JavaScript. Each BASIC statement could be turned into a JavaScript statement which did the same thing. (The reverse is not true: there are many features in JavaScript which do not have an equivalent in BASIC.)

This document isn't intended to teach you everything about JavaScript. It should give you enough of an introduction to get started and learn the basic forms of JavaScript.

Variable Types

JavaScript variables are not explicitly typed: they get their types from whatever is assigned to them. It's very similar to BASIC's Variant type.

Variables are declared with the VAR statement:

BASIC	JavaScript
Dim a	var a; var b,c; var d = 100;

In JavaScript, you can declare multiple variables in one statement. You can also assign an initial value.

Assignment

BASIC	JavaScript
a = 100	a = 100;
b = "Zaphod"	b = "Zaphod"; b = 'Zaphod';

There is no real difference between the languages. Note that JavaScript statements end with a semicolon (";"), rather than the end of the line. You are therefore allowed to break up statements into multiple lines.

Strings can be surrounded by matched single or double quotes. This make is much easier to have embedded quotes in strings.