Here's one more potential "low tech" solution for web based audio testing. We are starting to use ISpring software, which can be integrated and accessed through Powerpoint. It is more intuitive and accessible for those who have limited programming skills, though there are, of course, some quirks to get around. The software was developed for online education but has audio capabilities and testing options that make it suitable for many audio tests as well. I don't recommend it for psychoacoustic experiments where precision and timing is key, but for many suprathreshold perceptual listening tasks with speech, music and environmental sounds it seems suitable, at least on the first pass. But as I said, we are just starting to use it, so I don't have reliable data yet on lab vs. web comparisons.
Valeriy