WEBMIDI.js

https://webmidijs.org/docs
Admin
WEBMIDI.js is a JavaScript library that simplifies access to MIDI devices from web browsers and...
Tokens:8,051
Snippets:106
Trust Score:8.1
Update:5 months ago
Show doc for...
Tokens:
Raw
### Install WebMidi.js with NPM

Source: https://webmidijs.org/docs/getting-started/installation

Install the library using NPM. This command should be run at the root of your project. Node.js must be installed.

```bash
npm install webmidi
```

--------------------------------

### Idiomatic MIDI Device Interaction in v3

Source: https://webmidijs.org/docs/migration

An example of idiomatic v3 usage: getting an output by name, selecting a specific channel (channel 10), and playing a note. This demonstrates the streamlined approach to device and channel interaction.

```javascript
const output = WebMidi.getOutputByName("My Awesome Midi Device");  
const synth = output.channels[10];  
synth.playNote("A4");  
```

--------------------------------

### Link WebMidi.js from CDN

Source: https://webmidijs.org/docs/getting-started/installation

Include this script tag in your HTML to quickly get started with WebMidi.js using the jsDelivr CDN. This example uses the IIFE flavor.

```html
<script src="https://cdn.jsdelivr.net/npm/webmidi@next/dist/iife/webmidi.iife.js"></script>
```

--------------------------------

### Get MIDI Output by Name

Source: https://webmidijs.org/docs/getting-started/basics

Retrieve a reference to a MIDI output device using its name.

```javascript
const myOutput = WebMidi.getOutputByName("SP-404MKII");  

```

--------------------------------

### Get MIDI Input by Name

Source: https://webmidijs.org/docs/getting-started/basics

Retrieve a reference to a MIDI input device using its name.

```javascript
const myInput = WebMidi.getInputByName("MPK mini 3");  

```

--------------------------------

### Retrieve MIDI Output Ports

Source: https://webmidijs.org/docs/getting-started/basics

Get references to MIDI output ports using their ID, name, or by accessing the `WebMidi.outputs` array index. Note that IDs can vary between platforms.

```javascript
let output1 = WebMidi.getOutputById("123456789");  
let output2 = WebMidi.getOutputByName("Axiom Pro 25 Ext Out");  
let output3 = WebMidi.outputs[0];  

```

--------------------------------

### Include WebMidi.js IIFE in HTML

Source: https://webmidijs.org/docs/getting-started/installation

When using the IIFE (Immediately-Invoked Function Expression) flavor after installing with NPM, link to the script in your HTML page. This approach adds objects to the global namespace.

```html
<script src="node_modules/webmidi/dist/iife/webmidi.iife.js"></script>
```

--------------------------------

### Enable WebMidi.js

Source: https://webmidijs.org/docs/getting-started/basics

Call `WebMidi.enable()` to initialize the library. This method returns a promise that resolves when the library is ready.

```javascript
WebMidi  
  .enable()  
  .then(() => console.log("WebMidi enabled!"))  
  .catch(err => alert(err));  

```

--------------------------------

### List Available MIDI Inputs and Outputs

Source: https://webmidijs.org/docs/getting-started/basics

After enabling the library, iterate through `WebMidi.inputs` and `WebMidi.outputs` to log the manufacturer and name of available devices.

```javascript
WebMidi  
  .enable()  
  .then(onEnabled)  
  .catch(err => alert(err));  
  
function onEnabled() {  
    
  // Inputs  
  WebMidi.inputs.forEach(input => console.log(input.manufacturer, input.name));  
    
  // Outputs  
  WebMidi.outputs.forEach(output => console.log(output.manufacturer, output.name));  
  
}  

```

--------------------------------

### Enable WebMidi.js with Sysex Support

Source: https://webmidijs.org/docs/getting-started/basics

To use MIDI system exclusive messages, enable the library with the `sysex` option set to `true`.

```javascript
WebMidi  
  .enable({sysex: true})  
  .then(() => console.log("WebMidi with sysex enabled!"))  
  .catch(err => alert(err));  

```

--------------------------------

### Handle MIDI Permissions in Electron Main Process

Source: https://webmidijs.org/docs/going-further/electron

Configure Electron's main process to handle permission requests and checks for MIDI and MIDI Sysex permissions. This ensures that WEBMIDI.js can access MIDI devices within the Electron environment.

```javascript
mainWindow.webContents.session.setPermissionRequestHandler((webContents, permission, callback, details) => {
  if (permission === 'midi' || permission === 'midiSysex') {
    callback(true);
  } else {
    callback(false);
  }
})

mainWindow.webContents.session.setPermissionCheckHandler((webContents, permission, requestingOrigin) => {
  if (permission === 'midi' || permission === 'midiSysex') {
    return true;
  }
  return false;
});

```

--------------------------------

### Enable WebMidi.js and List Inputs

Source: https://webmidijs.org/docs

Enable WebMidi.js and display available MIDI input devices. This script should be placed in the head of your HTML page.

```javascript
<script type="module">
  
  // Enable WEBMIDI.js and trigger the onEnabled() function when ready
  WebMidi
    .enable()
    .then(onEnabled)
    .catch(err => alert(err));
  
  // Function triggered when WEBMIDI.js is ready
  function onEnabled() {
  
    // Display available MIDI input devices
    if (WebMidi.inputs.length < 1) {
      document.body.innerHTML+= "No device detected.";
    } else {
      WebMidi.inputs.forEach((device, index) => {
        document.body.innerHTML+= `${index}: ${device.name} <br>`;
      });
    }
  
  }
    
</script>

```

--------------------------------

### Enable WebMidi.js using Promises

Source: https://webmidijs.org/docs/migration

Demonstrates the new promise-based approach for enabling WebMidi.js. This is an alternative to the traditional callback method and is useful for asynchronous operations.

```javascript
WebMidi.enable().then(() => {  
  console.log("WebMidi.js has been enabled!");  
})
```

--------------------------------

### Play a note using a Note object

Source: https://webmidijs.org/docs/getting-started/basics

Create a `Note` object and pass it to the `playNote()` method.

```APIDOC
## Play a note using a Note object

### Description
Create a `Note` object and pass it to the `playNote()` method.

### Method
`output.playNote(note)`

### Parameters
- **note** (Note) - A `Note` object representing the note to play.
```

--------------------------------

### Play a Note using a Note Object

Source: https://webmidijs.org/docs/getting-started/basics

Create a Note object and pass it to the playNote() method for playback.

```javascript
const note = new Note("A4");  
const output = WebMidi.outputs[0];  
output.playNote(note);  
```

--------------------------------

### Include WebMidi.js Library

Source: https://webmidijs.org/docs

Link to the WebMidi.js library in the head of your HTML document.

```html
<!DOCTYPE html>
  
<html lang="en">
  
<head>
  <meta charset="UTF-8">
  <title>WebMidi.js Quick Start</title>
  <script src="https://cdn.jsdelivr.net/npm/webmidi@latest/dist/iife/webmidi.iife.js"></script>
</head>
  
<body>
  <h1>WebMidi.js Quick Start</h1>
</body>
  
</html>

```

--------------------------------

### Listen to Note On Event on InputChannel Object (v3 Idiomatic)

Source: https://webmidijs.org/docs/migration

The idiomatic v3 approach for listening to a 'noteon' event on a specific MIDI channel (channel 7) of the first input. This utilizes the dedicated InputChannel object for single-channel event handling.

```javascript
WebMidi.inputs[0].channels[7].addListener("noteon", someFunction);
```

--------------------------------

### Listen to Note On Event on Specific Channel (v2.5.x)

Source: https://webmidijs.org/docs/migration

This is the older syntax for listening to a 'noteon' event on a specific MIDI channel (channel 7) of the first input. While still functional in v3, a more preferred syntax is available.

```javascript
// In WebMidi.js version 2.5.x  
WebMidi.inputs[0].addListener("noteon", 7, someFunction);
```

--------------------------------

### Listen to Note On Event on Specific Channel (v3 Preferred)

Source: https://webmidijs.org/docs/migration

The preferred v3 syntax for listening to a 'noteon' event on a specific MIDI channel (channel 7) of the first input. This syntax is more explicit about channel targeting.

```javascript
WebMidi.inputs[0].addListener("noteon", someFunction, {channels: [7]});
```

--------------------------------

### Use Chained Methods

Source: https://webmidijs.org/docs/getting-started/basics

Chain multiple methods together for concise code.

```APIDOC
## Use Chained Methods

### Description
Most methods return `this`, allowing you to chain them together for more concise code.

### Example
```javascript
WebMidi.outputs[0].channels[8]
    .sendPitchBend(-0.25)
    .playNote("F4");
```
```

--------------------------------

### Listen for Note On Events on Multiple Channels

Source: https://webmidijs.org/docs

Add a listener directly on the input device to capture 'noteon' events across multiple specified channels.

```javascript
// Listen to 'note on' events on channels 1, 2 and 3 of the first input MIDI device
WebMidi.inputs[0].addListener("noteon", e => {
  document.body.innerHTML+= `${e.note.name} <br>`;
}, {channels: [1, 2, 3]});

```

--------------------------------

### Import WebMidi.js with ES Module in Browser

Source: https://webmidijs.org/docs/getting-started/installation

Import WebMidi.js using the ES Module format for use in modern browsers. Ensure the path to the module is correct.

```javascript
import {WebMidi} from "./node_modules/webmidi/dist/esm/webmidi.esm.min.js";
```

--------------------------------

### Listen to Event on Single Channel

Source: https://webmidijs.org/docs/getting-started/basics

Add a listener to a specific InputChannel to receive MIDI events like 'noteon'.

```javascript
WebMidi.inputs[0].channels[1].addListener("noteon", e => {  
  console.log(`Received 'noteon' message (${e.note.name}${e.note.octave}).`);  
});  
```

--------------------------------

### Listen for Note On Messages on All Channels

Source: https://webmidijs.org/docs/getting-started/basics

Add a listener to an `Input` object to react to 'noteon' messages from any channel. Logs the note identifier.

```javascript
const myInput = WebMidi.getInputByName("MPK mini 3");  
myInput.addListener("noteon", e => {  
  console.log(e.note.identifier);  
})  

```

--------------------------------

### Listen to event on multiple channels at once

Source: https://webmidijs.org/docs/getting-started/basics

Add a listener to an input to receive events from multiple channels.

```APIDOC
## Listen to event on multiple channels at once

### Description
Add a listener to an input to receive events from multiple channels simultaneously.

### Method
`input.addListener(type, listener, options)`

### Parameters
- **type** (string) - The type of MIDI event to listen for.
- **listener** (function) - The callback function to execute when the event occurs.
- **options** (object) - An object containing options for the listener.
  - **channels** (number[]) - An array of channel numbers to listen on. If omitted, listens on all channels.
```

--------------------------------

### Listen to event on single channel

Source: https://webmidijs.org/docs/getting-started/basics

Add a listener to a specific input channel to receive MIDI events.

```APIDOC
## Listen to event on single channel

### Description
Add a listener to a specific input channel to receive MIDI events.

### Method
`channel.addListener(type, listener, options)`

### Parameters
- **type** (string) - The type of MIDI event to listen for (e.g., "noteon", "controlchange").
- **listener** (function) - The callback function to execute when the event occurs.
- **options** (object, optional) - Additional options for the listener.
```

--------------------------------

### Play a note on multiple channels

Source: https://webmidijs.org/docs/getting-started/basics

Play a note on several MIDI channels simultaneously using the `playNote()` method of the `Output` object.

```APIDOC
## Play a note on multiple channels

### Description
Play a note on several MIDI channels simultaneously.

### Method
`output.playNote(note, channels)`

### Parameters
- **note** (string | Note) - The note to play (e.g., "Gb4").
- **channels** (number[]) - An array of channel numbers to play the note on.
```

--------------------------------

### Play a Note on a Specific MIDI Channel

Source: https://webmidijs.org/docs/getting-started/basics

Use the `playNote()` method on an `OutputChannel` object to play a note on a specific MIDI channel (e.g., channel 1).

```javascript
let output = WebMidi.outputs[0];  
let channel = output.channels[1];  
channel.playNote("C3");  

```

--------------------------------

### Import WebMidi.js with ES Module in Node.js

Source: https://webmidijs.org/docs/getting-started/installation

Import WebMidi.js using the ES Module format for use in Node.js v12+. This is the recommended approach for future development.

```javascript
import {WebMidi} from "webmidi";
```

--------------------------------

### Import WebMidi.js with CommonJS

Source: https://webmidijs.org/docs/getting-started/installation

Use this syntax to import WebMidi.js when working with CommonJS modules, typically in Node.js environments.

```javascript
const {WebMidi} = require("webmidi");
```

--------------------------------

### Listen for Note On Events on a Specific Channel

Source: https://webmidijs.org/docs

Retrieve a MIDI input device and add a listener for 'noteon' events on channel 1. This code should be placed within the onEnabled function.

```javascript
function onEnabled() {
  
  if (WebMidi.inputs.length < 1) {
    document.body.innerHTML+= "No device detected.";
  } else {
    WebMidi.inputs.forEach((device, index) => {
      document.body.innerHTML+= `${index}: ${device.name} <br>`;
    });
  }
    
  const mySynth = WebMidi.inputs[0];
  // const mySynth = WebMidi.getInputByName("TYPE NAME HERE!")
    
  mySynth.channels[1].addListener("noteon", e => {
    document.body.innerHTML+= `${e.note.name} <br>`;
  });
    
}

```

--------------------------------

### Listen for Note On Messages on a Specific Channel

Source: https://webmidijs.org/docs/getting-started/basics

Add a listener to a specific MIDI channel (e.g., channel 10) to react to 'noteon' messages. Logs the note identifier and channel.

```javascript
const myInput = WebMidi.getInputByName("MPK mini 3");  
const mySynth = myInput.channels[10]; // <-- the MIDI channel (10)  
  
mySynth.addListener("noteon", e => {  
  console.log(e.note.identifier, e.message.channel);  
})  

```

--------------------------------

### Listen to Event on Multiple Channels

Source: https://webmidijs.org/docs/getting-started/basics

Add a listener to an Input object to receive MIDI events from multiple channels by specifying the 'channels' option. If 'channels' is omitted, it listens to all channels.

```javascript
WebMidi.inputs[0].addListener("controlchange", e => {  
  console.log(`Received 'controlchange' message.`, e);  
}, {channels: [1, 2, 3]});  
```

--------------------------------

### Play a Note on Multiple Channels

Source: https://webmidijs.org/docs/getting-started/basics

Play a note on several MIDI channels simultaneously using the Output object. Specify the channels as an array.

```javascript
let output = WebMidi.outputs[0];  
output.playNote("Gb4", [1, 2, 3]);  
```

--------------------------------

### Play a note on a specific MIDI channel

Source: https://webmidijs.org/docs/getting-started/basics

Play a note on a specific MIDI channel using the `playNote()` method of the `OutputChannel` object.

```APIDOC
## Play a note on a specific MIDI channel

### Description
Play a note on a specific MIDI channel.

### Method
`channel.playNote(note)`

### Parameters
- **note** (string | string[]) - The note or chord to play (e.g., "C3" or ["C3", "D#3", "G3"]).
```

--------------------------------

### Chain WebMidi.js Methods

Source: https://webmidijs.org/docs/getting-started/basics

Chain multiple WebMidi.js methods together, as most methods return 'this' for fluent chaining.

```javascript
WebMidi.outputs[0].channels[8]  
    .sendPitchBend(-0.25)  
    .playNote("F4");  
```

--------------------------------

### Schedule notes

Source: https://webmidijs.org/docs/getting-started/basics

Schedule note playback in the future using absolute or relative time.

```APIDOC
## Schedule notes

### Description
Schedule note playback in the future using absolute or relative time.

### Method
`channel.playNote(note, options)`

### Parameters
- **note** (string) - The note to play.
- **options** (object) - An object containing time options.
  - **time** (number | string) - The time to schedule the note playback. Can be an absolute time (milliseconds since navigation start) or a relative time (e.g., "+2000").
```

--------------------------------

### Send Control Change Message to All Channels

Source: https://webmidijs.org/docs/migration

Sends a 'controlchange' message with a specified value to all channels of the first output. This demonstrates sending messages to all channels of an Output object.

```javascript
WebMidi.outputs[0].sendControlChange("resonance", 123);
```

--------------------------------

### Play a Note on a Specific MIDI Channel

Source: https://webmidijs.org/docs/getting-started/basics

Play a note or chord on a specific MIDI channel by accessing the OutputChannel object. The channel index is 1-based.

```javascript
let output = WebMidi.outputs[0];  
let channel = output.channels[1];  
channel.playNote(["C3", "D#3", "G3"]);  
```

--------------------------------

### Send Control Change Message to Specific Channels

Source: https://webmidijs.org/docs/migration

Sends a 'controlchange' message with a specified value to a subset of channels (1, 2, and 3) of the first output. This shows how to target multiple, but not all, channels.

```javascript
WebMidi.outputs[0].sendControlChange("resonance", 123, {channels: [1, 2, 3]});
```

--------------------------------

### Send All Sound Off Message

Source: https://webmidijs.org/docs/getting-started/basics

Use `sendAllSoundOff()` on an `Output` object to command a MIDI device to stop all sounds.

```javascript
const myOutput = WebMidi.getOutputByName("SP-404MKII");  
myOutput.sendAllSoundOff();  

```

--------------------------------

### Schedule Note Playback

Source: https://webmidijs.org/docs/getting-started/basics

Schedule note playback at a specific future time using the 'time' option. Time can be an absolute millisecond value or a relative string like '+2000'.

```javascript
WebMidi.outputs[0].channels[1].playNote("C3", {time: WebMidi.time + 3000});  
WebMidi.outputs[0].channels[1].playNote("C3", {time: "+2000"});  
```

--------------------------------

### Set polyphonic aftertouch

Source: https://webmidijs.org/docs/getting-started/basics

Send a polyphonic aftertouch message to a specific channel.

```APIDOC
## Set polyphonic aftertouch

### Description
Send a polyphonic aftertouch message to a specific channel.

### Method
`channel.sendKeyAftertouch(note, value)`

### Parameters
- **note** (string) - The note to send aftertouch for.
- **value** (number) - The aftertouch value (0 to 1).
```

--------------------------------

### Set Polyphonic Aftertouch

Source: https://webmidijs.org/docs/getting-started/basics

Send a polyphonic aftertouch message to a specific channel.

```javascript
WebMidi.outputs[0].channels[8].sendKeyAftertouch("B#3", 0.25);  
```

--------------------------------

### Set pitch bend value

Source: https://webmidijs.org/docs/getting-started/basics

Set the pitch bend value for a channel.

```APIDOC
## Set pitch bend value

### Description
Set the pitch bend value for a channel.

### Method
`channel.sendPitchBend(value)`

### Parameters
- **value** (number) - The pitch bend value, ranging from -1 to 1.
```

--------------------------------

### Check for Event Listener Presence

Source: https://webmidijs.org/docs/getting-started/basics

Verify if a specific event listener is attached to an InputChannel using the hasListener() method.

```javascript
let channel = WebMidi.inputs[0].channels[1];  
let test = e => console.log(e);  
channel.addListener('programchange', test);  
console.log("Has event listener: ", channel.hasListener('programchange', test));  
```

--------------------------------

### Sending a control change (CC) message

Source: https://webmidijs.org/docs/getting-started/basics

Send a control change message to a single channel or multiple channels.

```APIDOC
## Sending a control change (CC) message

### Description
Send a control change message to a single channel or multiple channels.

### Method
`output.sendControlChange(controller, value, options)` or `channel.sendControlChange(controller, value)`

### Parameters
- **controller** (number | string) - The controller number (0-127) or name (e.g., "volumecoarse").
- **value** (number) - The value for the control change (0-127).
- **options** (object, optional) - Options for sending to multiple channels.
  - **channels** (number[]) - An array of channel numbers to send the message to. If omitted, the message is sent to all channels.
```

--------------------------------

### Send Pitch Bend Message on a Specific Channel

Source: https://webmidijs.org/docs/getting-started/basics

Send a pitch bend message to a specific MIDI channel (e.g., channel 11) by accessing the `channels` property of an `Output` object.

```javascript
const myOutput = WebMidi.getOutputByName("SP-404MKII");  
const vocoder = myOutput.channels[11];  
vocoder.sendPitchBend(-0.5);  

```

--------------------------------

### Send Control Change Message to Single Channel

Source: https://webmidijs.org/docs/migration

Sends a 'controlchange' message with a specified value to a single, specific channel (channel 7) of the first output. This utilizes the OutputChannel object for single-channel message sending.

```javascript
WebMidi.outputs[0].channels[7].sendControlChange("resonance", 123);
```

--------------------------------

### Remove MIDI Listeners

Source: https://webmidijs.org/docs/getting-started/basics

Demonstrates how to remove MIDI event listeners from a specific channel. You can remove a single listener, all listeners for a specific event type, or all listeners on the channel.

```javascript
let channel = WebMidi.inputs[0].channels[1];
let test = e => console.log(e);
channel.removeListener("noteoff", test);  // specifically this one
channel.removeListener("noteoff");        // all noteoff on this channel
channel.removeListener();                 // all listeners

```

--------------------------------

### Specify Note Duration

Source: https://webmidijs.org/docs/getting-started/basics

Automatically stop a note after a specified duration by providing the 'duration' option in milliseconds.

```javascript
let output = WebMidi.outputs[0];  
let channel = output.channels[1];  
channel.playNote("C3", {duration: 1000});  
```

--------------------------------

### Specify note duration

Source: https://webmidijs.org/docs/getting-started/basics

Specify a duration for the note, and it will automatically be stopped after the duration has expired.

```APIDOC
## Specify note duration

### Description
Specify a duration for the note, which will automatically stop playback after the specified time.

### Method
`channel.playNote(note, options)`

### Parameters
- **note** (string) - The note to play.
- **options** (object) - An object containing duration options.
  - **duration** (number) - The duration of the note in milliseconds.
```

--------------------------------

### Set Pitch Bend Value

Source: https://webmidijs.org/docs/getting-started/basics

Set the pitch bend value for a channel. The value ranges from -1 to 1, where 0 means no bend.

```javascript
WebMidi.outputs[0].channels[8].sendPitchBend(-0.25);  
```

--------------------------------

### Manually stopping playback

Source: https://webmidijs.org/docs/getting-started/basics

Stop playback of a note immediately or in the future.

```APIDOC
## Manually stopping playback

### Description
Stop playback of a note immediately or in the future.

### Method
`channel.stopNote(note, options)`

### Parameters
- **note** (string) - The note to stop.
- **options** (object) - An optional object for scheduling the stop time.
  - **time** (number | string) - The time to stop the note. Can be an absolute time or a relative time (e.g., "+2500").
```

--------------------------------

### Control note velocity

Source: https://webmidijs.org/docs/getting-started/basics

Control attack and release velocities when playing a note using the `options` parameter.

```APIDOC
## Control note velocity

### Description
Control attack and release velocities when playing a note.

### Method
`channel.playNote(note, options)`

### Parameters
- **note** (string) - The note to play.
- **options** (object) - An object containing velocity options.
  - **attack** (number) - Attack velocity (0 to 1).
  - **release** (number) - Release velocity (0 to 1).
  - **rawAttack** (number) - Raw attack velocity (0 to 127).
  - **rawRelease** (number) - Raw release velocity (0 to 127).
```

--------------------------------

### Manually Stop a Note

Source: https://webmidijs.org/docs/getting-started/basics

Stop a note immediately or schedule its stop for a future time using the stopNote() method.

```javascript
WebMidi.outputs[0].channels[1].stopNote("C3");  
WebMidi.outputs[0].channels[1].stopNote("C3", {time: "+2500"});  
```

--------------------------------

### Check for the presence of an event listener

Source: https://webmidijs.org/docs/getting-started/basics

Check if a specific event listener is attached to a channel.

```APIDOC
## Check for the presence of an event listener

### Description
Check if a specific event listener is attached to a channel.

### Method
`channel.hasListener(type, listener)`

### Parameters
- **type** (string) - The type of MIDI event.
- **listener** (function) - The listener function to check for.

### Returns
- **boolean** - `true` if the listener is present, `false` otherwise.
```

--------------------------------

### Send Control Change Message

Source: https://webmidijs.org/docs/getting-started/basics

Send a control change (CC) message to a specific channel using controller number or name. Can also send to multiple channels or all channels.

```javascript
// Use controller number  
WebMidi.outputs[0].channels[1].sendControlChange(72, 64);  
  
// Use controller name  
WebMidi.outputs[0].channels[1].sendControlChange("volumecoarse", 123);  
```

```javascript
// Send to channels 1 through 3  
WebMidi.outputs[0].sendControlChange("pancoarse", 123, {channels: [1, 2, 3]});  
  
// Send to all channels  
WebMidi.outputs[0].sendControlChange(72, 56);  
```

--------------------------------

### Control Note Velocity

Source: https://webmidijs.org/docs/getting-started/basics

Control the attack and release velocities when playing a note using the 'options' parameter. Supports decimal values (0-1) or raw 7-bit values (0-127).

```javascript
let output = WebMidi.outputs[0];  
let channel = output.channels[1];  
channel.playNote("C3", {attack: 0.5});  
```

```javascript
let output = WebMidi.outputs[0];  
let channel = output.channels[1];  
channel.playNote("C3", {rawAttack: 123});  
```
Tokens:
Raw