A first version of a Sweet Home 3D viewer able to run under Android, and more generally in any HTML5 / WebGL browser was released recently.
It includes also a feature that lets you display an OBJ file stored in a ZIP file with its MTL and texture files with HTML5 / WebGL, using the viewModelInOverlay function available in the API of the new SweetHome3DJS library distributed under GNU General Public License. You can test this feature by clicking on the image of the 3D models shown at this page.
If you want to test it on your web site, you'll need the JavaScript files gl-matrix-min.js, jszip.min.js, core.min.js, triangulator.min.js and viewmodel.min.js, as well as the close.png image (< 250 Ko).