executing Javascript - TTS- iSpeech

I am working on a learning activity for which we want to use a hosted Text To Speech service (iSpeech).

The interaction is as follows:

1.       The user inputs text into the freeform Essay type Text-Entry-Box and clicks “Submit”

2.       The data in the Text-Entry-Box must be reported/stored to the LMS (-this work, thanks to the online community)

3.       *Simultaneously the user input must be read aloud using the iSpeech TTS.

4.       *Play next video/slide after the TTS audio plays and ends

I have attached files of TTS demo that supports Javascript, provided to me by iSpeech. I am trying to figure out how the TTS can be integrated with the learning activity.

Any help is greatly appreciated.

Thank you very much,

Vimal Guru