polly get audio function for AWS demo

app.js

// Polly Button click event handler from app.js
function (e) {
    var _app = this;
    if (e.dataset.voiceAudioContent) {
        _app.play(e.dataset.voiceAudioContent);
        return;
    } else {
        $.ajax({
            method: "POST",
            url: pollyFunctionURI,
            data: JSON.stringify({
                "data": {
                    "text": e.dataset.text,
                    "polly": {
                        "voice": "Matthew",
                        "format": "mp3",
                        "location": "text"
                    }
                }
            }),
        })
        .done(function(res) {
            e.dataset.voiceAudioContent = 'data:audio/mp3;base64,' + res.polly_sound;
            _app.play(e.dataset.voiceAudioContent);
        });
    }
}