Photo Sphere Viewer is a JavaScript library that allows you to display 360×180 degrees panoramas on any web page. Panoramas must use the equirectangular projection and they can be taken with Photo Sphere, the camera mode brought by Android 4.2 Jelly Bean.
Photo Sphere Viewer uses the Three.js library, so nothing is required for your visitors except for a browser compatible with canvas or, better, WebGL.
This library is available under the MIT license.