The Temasys Plugins bring support for webRTC to Desktop versions of Safari and IE:
https://confluence.temasys.com.sg/display/TWPP
Then only thing you need to do is to include a modified version of Adapter.js:
https://confluence.temasys.com.sg/display/TWPP/How+to+integrate+the+Temasys+WebRTC+Plugin+into+your+website