how to use sendmessage to call a unity function from html

Questions & Answers
1

The official doc says use SendMessage

SendMessage (‘MyGameObject’, ‘MyFunction’, ‘foobar’);

But after I built a webgl and add SendMessage to the released index.html, I got “SendMessage is undefined”. And I add this

var u=GetUnity();
u.SendMessage (‘MyGameObject’, ‘MyFunction’, ‘foobar’);

then I got GetUnity is undefined
How can I solve this problem

2

Just in case it helps you, I am using a template that works for me without problems, and I use SendMessage from index.html to Unity. I don’t need to use GetUnity(), just the bare SendMessage works for me on Chrome without problems. This code is used to get keys pressed from a MIDI keyboard and send them to the main program made in Unity in C#.

This is the complete index.html file that I am using at this moment, I hope that you can read it and use the information contained inside to solve your problem:

<!doctype html>
<html lang="en-us">
  <head>
    <meta charset="utf-8">
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <title>Unity WebGL Player | %UNITY_WEB_NAME%</title>
    <link rel="stylesheet" href="TemplateData/style.css">
    <link rel="shortcut icon" href="TemplateData/favicon.ico" />
    <script src="TemplateData/UnityProgress.js"></script>
  </head>
  <body class="template">
    <p class="header"><span>Unity WebGL Player | </span>%UNITY_WEB_NAME%</p>
    <div class="template-wrap clear">
    <canvas class="emscripten" id="canvas" oncontextmenu="event.preventDefault()" height="%UNITY_HEIGHT%px" width="%UNITY_WIDTH%px"></canvas>
      <div class="logo"></div>
      <div class="fullscreen"><img src="TemplateData/fullscreen.png" width="38" height="38" alt="Fullscreen" title="Fullscreen" onclick="SetFullscreen(1);" /></div>
      <div class="title">%UNITY_WEB_NAME%</div>
    </div>
    <p class="footer">« created with <a href="http://unity3d.com/" title="Go to unity3d.com">Unity</a> »</p>
    %UNITY_WEBGL_LOADER_GLUE%
    
    <script>
 	
//Bare minimum JS code to read midi input
//Adapted from https://github.com/cwilso/WebMIDIAPIShim

var midi;
var log = document.getElementById("midi-log");
//BRO_init();

function BRO_init() {

	logText("Inicializando MIDI...");
	navigator.requestMIDIAccess().then( onSuccess, onFailure ); //get midi access
}

function onSuccess( access ) {

	midi = access;
	var inputs = midi.inputs;

	logText("Encontrados " + inputs.size + " MIDI input(s)");

	//connect to first device found
	if(inputs.size > 0) {
	
		var iterator = inputs.values(); // returns an iterator that loops over all inputs
		var input = iterator.next().value; // get the first input
		logText("Primer input MIDI encontrado: " + input.name);
		input.onmidimessage = handleMIDIMessage;
	}
}

function onFailure( err ) {

	logText("MIDI Init Error. Error code: " + err.code);
}

function handleMIDIMessage(event){

//event.data & event.receivedTime are populated
//event.data has 3 components:
//0) The device id
//1) The controller id
//2) The controller value (typically in the range 0 - 127)

// mostramos sólo las pulsaciones y soltadas de tecla (códigos MIDI 144 y 128)
	if (event.data.length === 3 && (event.data[0] == 144 || event.data[0] == 128)) {
	
		var onOff = event.data[0];
		var nota = event.data [1];
		var volumen = event.data[2];
		if (onOff == 128) 
			volumen = 0;	
	
		//logText('mandato: ' + onOff + ', nota: ' + nota + ', volumen: ' + volumen);
		
		if (onOff == 144) {
		
			SendMessage("InputTecladoWebGL", "TeclaPulsadaDesdeNavegador", nota);
		}
		else if (onOff == 128) {
		
			SendMessage("InputTecladoWebGL", "TeclaLevantadaDesdeNavegador", nota);
		}
	}
}

function logText(str){

	/*
	log.innerHTML += str;
	log.innerHTML += "

";
log.scrollTop = log.scrollHeight;
*/
}

	</script>
	
  </body>
</html>