Javascript variable with example

 

what is a variable  JavaScript

 1] JavaScript variables are containers for storing information.

2]   JavaScript store data value.

JavaScript Variable 

1] var    

2] let

3] const

1] var   

   1]  JavaScript variables must identified with unique names.

  2]  Unique names call identifier.

 3]  identifier descriptive name is the (total volume,  age, sum).

 4]   Creating a variable  in JavaScript is declaring the variable.

Example :-

JavaScript Code :

    var a= 10;

    var b=20;

    var c= a+b;

    document.write(c);

Output :

2] let :-

 1] let statement separate the variables by comma.

2]  let can not be redeclared.

 

Example :-

JavaScript Code :

{

    let value = 50;

document.write("Inside the function

value = " + value);  

}

document.write("<br> Outside the function value = " + value);  

Output

3] const :-

  1] JavaScript  const is keyword use declare a variable .
  2]  const variable cannot be reassigned a new value.
  3]  const keyword declare a variable do not change the value.
  4] const variable creates only reference value.

Example :-

JavaScript Code :

const x = 90;  

     document.write("const variable value x = " + x);  

OutPut :-

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