Using Speak function in web apps

Is there any way to use the Speak function in a web app? I could make mp3 recordings of the audio output but that doesn’t quite meet my needs. [Note: In the past, we have used this approach with Acapela which has very high quality voices.]

I realize the function depends on what’s installed on the client. Is there an API that works across all browsers? I am thinking of trying out something like chrome.tts.