javascript string substring from end code example

Example 1: javascript get first 10 characters of string

var str = "Hello world That is reallly neat!";
var res = str.substring(0, 5);//get first 5 chars

Example 2: substring javascript

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

Example 3: cut string from string javascript

var ret = "data-123".replace('data-','');
console.log(ret);   //prints: 123