JavaScript for Beginners: Build real-time Projects

Like many other programming languages, JavaScript has variables.  You need variables to store data. Variables can be thought of as named containers. You can place data into these containers and then refer to the data simply by naming the container. 

Before you use a variable in JavaScript program, you must declare it. Variables are declared with the var keyword.

Storing a value in a variable is called variable initialization. You can do variable initialization at the time of variable creation or at a later point in time when you need that variable.

In this tutorial, we will use a variable to store a number. In this tutorial, we will create three variables and values are assigned to these variables. 

In this tutorial, we will see how to use Quotes inside a String. Sometimes you will want to use a double of single quote mark within a string. 

Because strings can live in single or double quotes, if you just want to use double quotes in the string, you could surround the entire string in single quotes. If you just want to use single quotes in the string, you could
surround the string in double quotes.

You can also use a technique called escaping the quotation characters. This is done by using a backwards slash (or "backslash") before any type of quote mark that appears within a string.The backwards slash tells the interpreter that the following character is part of the string, rather than the end of it.

In this tutorial, we will learn about rules for naming variables. 

In this tutorial, we will learn about Arrays. An array is a special type of variable. It doesn't just store one value,it stores a list of values. 

You should consider using an array whenever you are working with a list or a set of values that are related to each other.

Arrays are especially helpful when you do not know how many items a list will contain because, when you create the array, you do not need to specify how many values it will hold.

For example:

var colors;  
colors =['white', 'black', ' custom '];

In this tutorial, we will learn about how to declare an array. 

You create an array and give it a name just like you would any other variable (using the var keyword followed by the name of the array).

Note:  The values are assigned to the array inside a pair of square brackets, and each value is separated by a comma. The values in the array do not need to be the same data type, so you can store a string, a number and a Boolean all in the same array.

var colors= ['white', 'black', 'custom'];

What is an operator?

Let us take a simple expression 4 + 5 is equal to 9. Here 4 and 5 are called operands and ‘+’ is called the operator. JavaScript supports the following types of operators.

• Arithmetic Operators

• Comparision Operators

• Logical (or Relational) Operators

• Assignment Operators

• Conditional (or ternary) Operators

JavaScript supports the following arithmetic operators −

1.     + (Addition)
2.      -(Subtraction)
3.     * (Multiplication)
4.      / (Division)
5.     % (Modulus)
6.    ++ (Increment)
7.     -- (Decrement)

There is just one string operator: the+ symbol. It is used to join the strings on either side of it.

var firstName = 'Ivy ' ;
var lastName = ' Stone' ;
var fullName = firstName + lastName;

full Name would hold the string 'Ivy Stone'.

This example tutorial combines several techniques that you have seen throughout this section.

WHAT IS A FUNCTION?

Functions let you group a series of statements together to perform a specific task. If different parts of a script repeat the same task, you can reuse the function (rather than repeating the same set of statements).