Mixing loops with Web Audio API can now be done easily by the whole family. Web Audio Loop Mixer is a Web Audio App that uses the Web Audio API to recreate an audio mixer. It has four channels and global effects that can be applied to any channels. The Web Audio Loop Mixer is a virtual mixer based on the work I did for my Channel Strip. It allows up to four audio loops to be boosted, attenuated, equalized, panned, muted, and effected with delay or distortion in the browser.
Or check out the official Web Audio Loop Mixer Documentation Page