JavaScript is the object-oriented programming language. It is cross-platform, interpreted, and dynamic programming language. This programming language is a translated one. JavaScript has easy integration with HTML, so it is very easy to implement. JavaScript is a lightly weighted programming language used for creating the network-centric application. At first the JavaScript was known as LiveScript, but afterwards, Netscape changed its name to JavaScript because this language mostly uses the excitement of Java. The JavaScript programming language development was in 1995 as LiveScript with the appearance in Netscape 2.0. The basic core of this language is part of Netscape, Internet Explorer, and another web browsers. Hire freelancers online who have at least basic knowledge of programming.

Syntax for JavaScript:

JavaScript is implemented using <script>…..</script> tag


JavaScript Code


JavaScript Variable:

The name of the storage location is known as JavaScript variable. The JavaScript variable has two types that are the local variable and global variable. The name of the variable must start with a letter, underscore or with a dollar sign($). The variable of JavaScript must be case sensitive. After the first letter of JavaScript variable, you can use digits 0 to 9, e.g., numer1.

Variable declaration:

var a=5;


JavaScript Data Type:

The JavaScript data type has two types

  • Primitive data type
  • Non-primitive data type

Primitive data type in JavaScript

  1. String: The sequence of character is known as string data type for ex “abc.”
  2. Number: The number data type represents the numeric value for ex 100.
  3. Boolean: Boolean data type only represents two values that are either true or false.
  4. Undefined: It signifies only undefined value.
  5. Null: Null data type represents no value at all.

Non-primitive data type in JavaScript

  1. Object: Object data type represents the instance using that you can access members.
  2. Array: The array data type represents a group of similar values.
  3. RegExp: RegExp represents the regular expression.

JavaScript Loop:

If you want to perform the repetitive task on a piece of code, then that time loop performs the important task in a programming language. You can find freelance jobs online from various available marketplace websites.

Types of loop

  1. for loop
  2. while loop
  3. do…while loop
  4. for-in loop

JavaScript for loop

The for loop in JavaScript perform the repetitive task for the fixed number of time.

Syntax of for loop:

for (initialization; condition; increment)


code for execution


JavaScript while loop

The while loop performs the repetitive task for the infinite number of times.

Syntax of while loop:

while (condition)


code for execution


JavaScript do….while Loop

do…while loop is same as the while loop only difference is that it executes the statement irrespective of condition.

Syntax for do…while loop


code to be executed

}while (condition);

JavaScript for…in Loop

This loop works on the object properties. Unless you understand the properties of an object, you will not understand the concept of that loop.

Syntax of for…in loop

for (variablename in object){

statement or block to execute


JavaScript Function:

The function allows the programmer to reuse the code in the program many times because of this feature there is the elimination of writing code again and again. The function enables a programmer to write a big code in small manageable functions.


Function functionName([arg1, arg2,…argN])





The array is the collection of fixed size similar type of data type. The array allows the programmer to store multiple values in a single variable.

var flower=new Array( “lilly”, “lotus”, “rose”);

JavaScript Errors:

JavaScript syntax errors are parsing errors. This error occurs at compile time in other programming language and at interprets time in JavaScript programming.

<script type=”text/javascript”>





In above program syntactical error is on closing of parenthesis.

Logical Errors:

Tracking the logical error is a more difficult type of error. The logical error occurs when you make a mistake in the logic of a program.

Exception Handling:

Now JavaScript programming added the concept of exception handling. The exception is handling in JavaScript through try… catch….finally construct and throw operator is used to handle the exception. One should always find freelance jobs online from trusted sources.

Syntax of try…catch…..finally block

try {         // Code to run




catch ( e ) {

// Code to run if an exception occurs




[ finally {

// Code that is always executed regardless of

// an exception occurring



This article is in the JavaScript tutorial. This tutorial covers all the important basic and advance topic of JavaScript programming language. This tutorial is very helpful to those programmers who want to work in JavaScript programming language.

Kitty Gupta