Learning JavaScript tutorial – JavaScript Variables

JavaScript Variables are the main building blocks of JavaScript Scripting language. JavaScript Variables are used for storing (contains) the data (value) and manipulate that data in your programs.

Every JavaScript variable has a name, called its ‘identifier’ and optional data called ‘Literals’. JavaScript Variables are declared using JavaScript ‘var’ keyword. JavaScript var keyword allocates storage space for variable to store data. Multiple variables can be declared with one JavaScript ‘var’ keyword. The main advantage of JavaScript variable is, it can hold a value of any data type. Using an undeclared variable causes an error. The best practice of defining JavaScript Variables is with assigned initial values.

var intNum;  //variable intNum is declared
var intNum=10; //variable declared with assigned initial values
var x=5, y=4, z=x+y; //multiple variables with one var keyword

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Learning JavaScript tutorial – JavaScript Literals and Identifiers

JavaScript Literals

JavaScript Literals are the notation for representing a fixed data value that appears directly in a JavaScript program. JavaScript Literals helps us to assign values (initialize) to various JavaScript Data Types and Variables; such as integers, floating-point numbers, strings, and Booleans; enumerated Data Types and compound values such as arrays, records, and objects.

var intNum = 82    // 82 is a integer literal
var PI = 3.14        // 3.14 is a float literal
var strInfo="This is a string" // this is a string literal
var strGreet=‘Hello!’;   // another string literal
var isMale=true          // A Boolean value literal
var arrAnimal={"cat","dog"}    // array literals

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Learning JavaScript tutorial – JavaScript Comments

JavaScript Comments allows us to add remarks and a well written explanation about the working of JavaScript code. JavaScript Comments make the code more readable, understandable for future reference. Commenting your JavaScript code makes it easier for others to understand. To increase re-usability of a JavaScript code be, sure to include comments in your scripts. Commenting your JavaScript code is the best practice of JavaScript programming and suits to your aspect of good programming style.

Any comments you include in your JavaScript code will simply ignored by the JavaScript interpreter. JavaScript supports both C++ and C-style comments. JavaScript supports two types of comments, Single-line comments and multiple-line comments.

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Learning JavaScript tutorial – Lexical Structure and Statements

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A JavaScript statement is a command to a web browser to perform specific task define (program written) by the user. JavaScript Statements are written with the set of elementary rules that specifies how to write JavaScript programs. A JavaScript program is a set of one or more statements. A statement will have internal components like Variables, Literals, Identifier, reserved keywords, Comments, conditional statement, Arrays, Functions, Objects, Classes etc

JavaScript is case sensitive, in the most of cases JavaScript Statements terminated with a semicolon(;) or with Returns(Enter or line-break). Even though semicolon is optional, JavaScript Statements terminated with a semicolon(;) is the best practice of JavaScript programming.

var txtName="I love JavaScript";
var intNum=10

semicolons allows us to group multiple statements on one line.

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Learning JavaScript tutorial – First Look at Client-Side JavaScript

As we seen in our first article "Learning JavaScript – an introduction with JavaScript", JavaScript is mostly used as a client-side scripting language. With Client-side JavaScript, we are able to interpreter with the Document Object Model (DOM) of a web browser. On Client-Side, JavaScript add interactive features to your page. JavaScript allowing us to do plenty of tasks on Client-Side like mathematical calculations, form validation, drop down and sliding menus, message tickers, work with events, work with cookies, add special effects and animation, develop interactive games, customize graphics selections, and create security passwords and many more.

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