The web browser provides a novel platform for interactive music with a number of unique advantages: easy access, online collaboration, platform independence and abundant online resources. The goals of this chapter are (1) to help readers comprehend the benefits and challenges involved in developing and using browser-based interactive music applications; (2) to provide a basic technical foundation for writing a Web Audio program in the context of creating interactive music applications; and (3) to explore the opportunities that interactive music on the web offers, by identifying the five emerging trends of current music applications. Ultimately, we wish to encourage readers to create applications that permit novel musical expression and collaboration through the use of Web Audio.