The split() method splits a string into an array of strings.

Syntax

str.split(separator[, limit]);

separator Optional. The separator specifies which characters to use for separating the string. If separator is omitted str.split(); the array will contain just one element consisting of the entire string. If separator is an empty string str.split(""); the string is converted into an array of characters.

limit Optional. Whole number integer that sets a limit to the number of splits that can be found. The split() method will still find all of the matches to the separator, but will truncate the returned array to a maximum length of limit elements.

The split() method returns the new array.

At each match of the separator .split() will split the string and add the split section as an element to an array.

Splitting a string into an array of substrings

var str = "HelloWorld";
console.log(str.split(""));
// Console will output: ["H", "e", "l", "l", "o", "W", "o", "r", "l", "d"]

var str2 = "HelloWorld";
console.log(str2.split());
// Console will output: ["Hello World"]

var str3 = "HelloWorld";
console.log(str3.split("Wo"));
// Console will output: ["Hello", "rld"]

Source MDN