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Javascript-Data types

 

Two types of data types in JavaScript:

  1. Primitive data type
  2. Non-primitive (reference) data type

 

primitive data types:

 

Five types of primitive data types in JavaScript:

  1. String              –           sequence of characters e.g. “hello”
  2. Number –           numeric values e.g. 100
  3. Boolean –           boolean value either false or true
  4. Undefined –           represents undefined value
  5. Null –           represents null i.e. no value at all

 

1. string:

 

Syntax:

 

var name = "I2tutorials";

 

Example:

 

<!DOCTYPE html>
<html>
<body>

<h2>JavaScript Strings</h2>

<p id="demo"></p>

<script>
var carName1 = "i2tutorials";
var carName2 = 'javascript';

document.getElementById("demo").innerHTML =
carName1 + "<br>" +
carName2;
</script>

</body>
</html>

 

OUTPUT

 

Javascript-Data types

 

2. Number:

 

Syntax:

 

var age = 19;

 

Example:

 

<!DOCTYPE html>
<html>
<body>

<h2>JavaScript Numbers</h2>

<p>with decimals, or without decimals:</p>

<p id="demo"></p>

<script>
var x1 = 34.00;
var x2 = 34;
var x3 = 3.14;

document.getElementById("demo").innerHTML =
x1 + "<br>" + x2 + "<br>" + x3;
</script>

</body>
</html>

 

OUTPUT:

 

Javascript-Data types

 

3.Boolean

 

Syntax:

 

var truth = false;

 

Example:

 

<!DOCTYPE html>
<html>
<body>

<h2>JavaScript Booleans</h2>

<p id="demo"></p>

<script>
var x = 5;
var y = 5;
var z = 6;
document.getElementById("demo").innerHTML =
(x == y) + "<br>" + (x == z);
</script>

</body>
</html>

 

OUTPUT:

 

Javascript-Data types

 

4. undefined

 

Syntax:

 

var a; typeof a;

 

Example:

 

<!DOCTYPE html>
<html>
<body>

<h2>JavaScript undefined</h2>

<p id="demo"></p>

<script>
var car;
document.getElementById("demo").innerHTML =
car + "<br>" + typeof car;
</script>

</body>
</html>

 

OUTPUT:

 

Javascript-Data types

 

5. null

 

Syntax:

 

var a = null;

 

Example:

 

<!DOCTYPE html>
<html>
<body>

<h2>JavaScript null</h2>

<p id="demo"></p>

<script>
var person = {firstName:"i2", lastName:"tutorials", age:50, eyeColor:"blue"};
person = null;
document.getElementById("demo").innerHTML = typeof person;
</script>

</body>
</html>

 

OUTPUT:

 

Javascript-Data types 

 

 2.non-primitive data types:

 

  1. Object –           instance through which we can access members
  2. Array –           represents group of similar values
  3. RegExp –           represents regular expression

 

syntax : object:

 

var name = {first:"I2", last:"tutorials"};

 

Syntax: array

 

var sheets = ["html","css","javascript"];