What Is JavaScript?
JavaScript, also known as JScript and EcmaScript, is a scripting language that is primarily used to affect web pages’ behavior. Unlike languages such as Java, PHP, Perl and others, which need the code to be translated by the server and the results sent back to the web page’s visitors, JavaScript is interpreted by the browser itself. It is said, then, that JavaScript is a Client side language. Client, meaning the browser as opposed to the Server which is usually in a remote location.
fbernall on 08/02/2009
JavaScript Basics •
All languages have some form of structure, lexicon, punctuation, unique words, etc. Like spoken languages, a programming language often traces its syntax to another language. Such is the case with JavaScript which shares similar syntax to C/C++ and Java (the fact that JavaScript’s syntax is in some ways similar to Java, does not mean that the languages are related). JavaScript also shares code similarities with Perl in the use of Regular Expressions a topic we’ll explore in future articles.
A variable is simply a container. A variable tells the computer to set some “space” aside in memory, and that something of value is being stored in that space or will be stored later on. Many metaphors have been used to define a variable. A box, for example, has been the classic analogy to describe a variable. My metaphor is the pockets in my pants. Each pocket has a name: frontRightPocket, frontLeftPocket, rearRightPocket, rearLeftPocket. Each pocket can be initially empty, or already have something inside of “value”. I can always add new pockets to my pants if I need to and can also remove pockets if I so desire.
Similar to languages such as Java, C, C++, Operators in JavaScript are symbols or keywords that perform arithmetic functions, compare values, assign values to variables, increment or decrement values. They are an integral aspect of logic and a good grasp is essential for successful programming. As in algebra, JavaScript operators have an order of precedence and associativity. In this chapter we will cover the major operators types currently in use as of this writing including: Arithmetic Operators, Assignment Operators, Comparison Operators, String Operators, Conditional Operators, Logical Operators.