Is it possible to select the word that is being read while using the SpeechSynthesisUtterance API?
Is there an event I can use to get the current spoken word and cursor position?
Here is what I have so far:
var msg = new SpeechSynthesisUtterance();
var voices = window.speechSynthesis.getVoices();
msg.voice = voices[10]; // Note: some voices don't support altering params
msg.voiceURI = 'native';
msg.volume = 1; // 0 to 1
msg.rate = 1; // 0.1 to 10
msg.pitch = 2; //0 to 2
msg.text = 'Hello World';
msg.lang = 'en-US';
msg.onend = function(e) {
console.log('Finished in ' + event.elapsedTime + ' seconds.');
};
speechSynthesis.speak(msg);
Example from here.
There was a related question that wrote out the words out to a span and I've extended that answer here to select the words as they are spoken.
var utterance = new SpeechSynthesisUtterance();
utterance.lang = 'en-UK';
utterance.rate = 1;
document.getElementById('playButton').onclick = function(){
var text = document.getElementById('textarea').value;
// create the utterance on play in case user called stop
// reference https://stackoverflow.com/a/47276578/441016
utterance = new SpeechSynthesisUtterance();
utterance.onboundary = onboundaryHandler;
utterance.text = text;
speechSynthesis.speak(utterance);
};
document.getElementById('pauseButton').onclick = function(){
if (speechSynthesis) {
speechSynthesis.pause();
}
};
document.getElementById('resumeButton').onclick = function(){
if (speechSynthesis) {
speechSynthesis.resume();
}
};
document.getElementById('stopButton').onclick = function(){
if (speechSynthesis) {
speechSynthesis.cancel();
}
};
function onboundaryHandler(event){
var textarea = document.getElementById('textarea');
var value = textarea.value;
var index = event.charIndex;
var word = getWordAt(value, index);
var anchorPosition = getWordStart(value, index);
var activePosition = anchorPosition + word.length;
textarea.focus();
if (textarea.setSelectionRange) {
textarea.setSelectionRange(anchorPosition, activePosition);
}
else {
var range = textarea.createTextRange();
range.collapse(true);
range.moveEnd('character', activePosition);
range.moveStart('character', anchorPosition);
range.select();
}
};
// Get the word of a string given the string and index
function getWordAt(str, pos) {
// Perform type conversions.
str = String(str);
pos = Number(pos) >>> 0;
// Search for the word's beginning and end.
var left = str.slice(0, pos + 1).search(/\S+$/),
right = str.slice(pos).search(/\s/);
// The last word in the string is a special case.
if (right < 0) {
return str.slice(left);
}
// Return the word, using the located bounds to extract it from the string.
return str.slice(left, right + pos);
}
// Get the position of the beginning of the word
function getWordStart(str, pos) {
str = String(str);
pos = Number(pos) >>> 0;
// Search for the word's beginning
var start = str.slice(0, pos + 1).search(/\S+$/);
return start;
}<textarea id="textarea" style="width:100%;height:150px;">
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</textarea><br>
<input type="button" id="playButton" value="Play"/>
<input type="button" id="pauseButton" value="Pause"/>
<input type="button" id="resumeButton" value="Resume"/>
<input type="button" id="stopButton" value="Stop"/>