Variables
Variables are the containers for storing information or a data. In Javascript , it can be declared in three ways:
1.var 2.let 3.count
1.var keyword – function scope or global scope. var variables can be re-declared and updated
var x=10 { var y=20 } console.log(y) //output: 20
2. let keyword-block scope. let is only available for use within that block.
{ let x=20 console.log(x) } //output:20
3.const keyword – block scope. const cannot be updated or re-declared.
function myscript() { const a = 30; a = 40; // TypeError: Assignment to constant variable } myscript();
Operators
Javascript operators are used to perform operations on values and variables in different types of mathematical and logical computations.
Examples:
Assignment Operator : = assigns values between the variables
Addition Operator : + adds values between the variables
Multiplication Operator : * multiplies values between the variables
Comparison Operator : > compares values between the variables
Functions
In JavaScript, function is defined with the function
keyword, followed by a name, followed by parentheses () designed to perform a particular tasks. The parentheses may include parameter names separated by commas like (a,b…)
Parameters refers to the variables or placeholder that you define when declaring a function. It serves as a inputs to the function and allows to pass data into a function.
function area(l,b) { result=l*b console.log(result) } area(10,5) //output:50