Allowing user to add audio to an app or website

I'm developing a learning resource for chronically ill children and I want to add a "reward" whereby the child can record their voice over the module when they are finished and send it on. I have seen it in operation in "The Cat in the Hat" published by Ocean House media but cannot find any information on it. I am relatively HTML5 JavaScript and PHP literate so any code is welcome. Thanks a million reg