I "fixed" the Internet Explorer issue, though it still doesn't run nearly as well as Chrome or Firefox. (I haven't tested Safari.) 

I upgraded to the most current version of Leaflet (the maps I use). I have put it off since there are some things in the new version that broke the maps. I spent tonight going through those and fixing what the new version broke, but I may have missed something. Let me know if everything still works or if you run into any problems.