Working with JavaScript

Java or JavaScript? And, what's the difference?

Java is a programming language developed and controlled by Sun Microsystems. It is proprietary, licensed, and readily available on a number of platforms.

JavaScript was developed by Netscape as a scripting language for its browsers.

The difference between Java and JavaScript is roughly the same as the difference between C/C++ and Java (or C/C++ and JavaScript). There are similar syntax requirements, and some of the names are the same (or sufficiently similar that it is easy to figure out what's what). For many years, C and C++ have been the programming languages of choice for many applications and systems. Unix, Linux, and Windows contain extensive C and C++ code. Even Firefox has thousands of C and C++ source files.

JavaScript Reference

I'm including a simple JavaScript reference here. For a more complete reference, try http://wp.netscape.com/eng/mozilla/3.0/handbook/javascript/, which contains tutorial and reference sections. JavaScript supports operations (assignments, math, and so on), conditionals (if, loop, and so forth), objects, and functions. JavaScript statements are

• break This immediately ends a while or for loop.

• comment This inserts a comment into the JavaScript code.

• continue This ends the current iteration of a loop and begins a new iteration. Essentially, it skips following statements.

• for This is a basic looping structure in which the start, condition, and increment can be specified.

• for...in This iterates the variable for all properties in an object.

• function This creates a function that can be called from multiple locations. Optionally, it returns a value.

• if...else This is the basic conditional test block.

• new This creates a new array, Boolean, date, functions, math, number, or string object.

• return This returns from a function, optionally passing back a return value.

• this This is a reference to the current object.

• var This declares and initializes a variable. It is not an error to initialize a variable, but it is bad programming practice.

• while This creates a conditional loop structure that is executed as long as the condition is true.

• with This allows you to specify a default object for a collection of statements.