how to reference the first letter of a word using javascript code example

Example 1: js get words first letter

var str = "Java Script Object Notation";
var matches = str.match(/\b(\w)/g); // ['J','S','O','N']
var acronym = matches.join(''); // JSON

console.log(acronym)

Example 2: javascript get first letter of each word

var msg = "Name Surname a"
var acronym = msg.match(/\b(\w)/g).join('');

console.log(acronym)