use of 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: substring javascript

var str = "Hello world!";
var res = str.substring(1, 4); //ell