AND IT IS SUPER ANNOYING.
It’s breaking in my IE9 for various reasons, perhaps mainly because the js is being included via a weird, legacy templating system out of my control.
By default, Visual Studio uses UTF encoding with the BOM; however, you can save it to a different encoding if you’d prefer. When you go to the Save As dialog, you can expand the Save button to see the ‘Save with Encoding’ option. This will prompt you for a different encoding, and I think one of the Unicode options will leave out the BOM (somewhere in the list is UTF-8 without signature).