what is substr and substring in javascript code example

Example 1: js substring

// the substring method returns a string out of another string

const str = 'Mozilla';

console.log(str.substring(1, 3));
// expected output: "oz"

console.log(str.substring(2));
// expected output: "zilla"

Example 2: js .substring

let anyString = 'Mozilla'

// Displays 'M'
console.log(anyString.substring(0, 1))
console.log(anyString.substring(1, 0))

// Displays 'Mozill'
console.log(anyString.substring(0, 6))

// Displays 'lla'
console.log(anyString.substring(4))
console.log(anyString.substring(4, 7))
console.log(anyString.substring(7, 4))

// Displays 'Mozilla'
console.log(anyString.substring(0, 7))
console.log(anyString.substring(0, 10))