Using Google Text-To-Speech in Javascript

Here is the code snippet I found:

var audio = new Audio();
audio.src ='http://translate.google.com/translate_tts?ie=utf-8&tl=en&q=Hello%20World.';
audio.play();

Another option now may be HTML5 text to speech, which is in Chrome 33+ and many others.

Here is a sample:

var msg = new SpeechSynthesisUtterance('Hello World');
window.speechSynthesis.speak(msg);

With this, perhaps you do not need to use a web service at all.