According to recent posts online, Mozilla Firefox 64bit is likely to see Microsoft Silverlight integrated into one of its upcoming release in near future – date and version yet unknown. Based on speculation, Silverlight would be available on Mozilla Firefox 44 which is currently in Dev stage. At least for a while as Mozilla still plans on deprecating Silverlight support sometime in the future (much as Google and Microsoft already have).
Pipelight an alternative to Silverlight for ubuntu, is a special browser plugin which allows one to use windows only plugins inside Linux browsers by embedding Silverlight directly in any Linux browser that supports Netscape Plugin API (Firefox, Google Chrome / Chromium, Opera…). Pipelight consists out of two parts: A Linux library which is loaded into the browser and a Windows program started in Wine. The Windows program, called pluginloader.exe, simply simulates a browser and loads the Silverlight DLLs.