JavaScript Basics

JavaScript is a scripting language which makes the webpages more interactive.

Like, adding a calculator or a quiz in the webpage, JavaScript is needed.

We require notepad ++ for writing JavaScript commands.

<Script> </Script>  tags should be added so that the browser will know which scripting language we are using.

Example:

<Script type = “javascript”> </Script> 

A variable is nothing but a placeholder.

X = Chocolate

Kids love X.

X is made from Cocoa.

Similarly, in JavaScript, the variable is represented as ‘var’.

var x = 25;

document.write(x);

Result: 25

Different types of variables:

The numbers  can be stored by declaring “var”.

The words can be stored by adding quotation marks “apple”

When you add words like:

var fruit = “Amanda said, “I like oranges””;

Result: <empty page>

We need to add escape characters so that it gets printed:

var fruit = “Amanda said, \“I like oranges\” ”;

Result: Amanda said, “I like oranges”.

We can use escape character if we need to escape something from the result.

In order to use variables and strings together, mention it with “+”.

var fruit = “Orange”;

var color = “Black”;

document.write(fruit + “is my favorite” );

Result: Orange is my favorite

Functions:

The function is defined with the function keyword.

You can use a function declaration and get real values when invoked.

function fruit()

{

alert(“Berry!”);

}

fruit();

In order to use function in HTML:

<form>

<input type =”button” value=”pineapple” onclick=”fruit()”>

</form>

Passing values into function

function fruit(x){

alert(“I love”+x);

}

fruit(“Apple”);

fruit(“Banana”);

fruit(“Cranberry”);

Passing multiple parameters in function:

function fruit(one, two){

document.write(one + “ is better than “+ two + “<br/>”);

}

fruit(“Cranberry”,”Blueberry”);

fruit(“Dog”,”Cat”);

fruit(“Rose”,”Jasmine”);

Result:  Cranberry is better than Blueberry

              Dog is better than Cat

              Rose is better than Jasmine

Return statement:

Return is to return the value passed by parameters in a function.

function addNumbers(a, b){

var c = a+b;

return c;

}

document.write(addNumbers(3,2));

Result:  5

Reference: https://thenewboston.com