JavaScript notes

Format number:
```
(123456789).toLocaleString()
```
will returns:
```
123,456,789
```
.
Padding 0:
```
(123).toString().padStart(6, "0")
```
will returns:
```
000123
```
.
Padding spaces:
```
(123).toString().padStart(6)
```
will returns:
```
   123
```
.
Check is substring exists:
```
("abcde").includes("bc")
```
will returns:
```
true
```
.
Check if an item exists in an array:
```
["a","b","c"].includes("b")
```
will returns:
```
true
```
.
Check if string starts with:
```
"abcde".startsWith("abc")
```
will returns:
```
true
```
.
Check if string ends with:
```
"abcde".endsWith("cde")
```
will returns:
```
true
```
.
Check if the visitor is Malaysian:
```
(new Date()).toString().includes("Malaysia")
```
will returns:
```
true
```
if the visitor is Malaysian.

TTS (Text-To-Speech):

// ENTER SETUP
// ===========
let t = "hello world";
// LEAVE SETUP
// ===========

let ss     = window.speechSynthesis;
let voices = [];

ss.onvoiceschanged = ()=>{
  voices = ss.getVoices();
};
voices = ss.getVoices();

let ssu = new SpeechSynthesisUtterance(t);
ssu.voice = voices[0];
ss.speak(ssu);

Check if the DOM is loaded:

document.addEventListener("DOMContentLoaded", (ev)=>{
  console.log("DOM fully loaded and parsed");
});

Reload current page:
```
history.go();
```
.

Regular expression capture group (.*?) and do action on the captured group:

function replacer(match, capture1, offset, original_string) {
  let n = parseFloat(capture1);
  
  return "output: " + n*2;
}

let s = "[tag]3[/tag]";

s.replace(/\[tag\](.*?)\[\/tag\]/gi, replacer);

will returns:

output: 6