While investigating some localization options, I stumbled across this as a save option in Visual Studio.
What is Unicode code page 1200 exactly?
The Microsoft documentation page Code Page Identifiers describes:
Unicode UTF-16, little endian byte order (BMP of ISO 10646); available only to managed applications
So is Unicode code page 1200 really UTF-16 and therefore has a BOM?
Is it advisable to use this for JavaScript then, and if we have to use this, is a charset
declaration necessary in the script tag?
Code page 1200 is UTF-16 little endian, and does not imply BOM or not. For anything web use UTF-8 (everything: css, html, javascript, etc.)