This demo uses the Basis C++ transcoder (compiled to Javascript using Emscripten) to transcode a .basis file to BC1/BC3.
Thanks to Evan Parker for providing webgl-texture-utils and this test bed.
.basis file:
NOTE: Your browser does not support DXT, so using RGB565
for the texture below. To get DXT, try Chrome 19+
(beta channel as of 2012-04-20; graphics card DXT support also required).