I'm building a web-based application that can use ActiveX Controls to print to a Thermal Label Printer (specific to shipping labels) in Windows environments, but I am racking my brain to figure out what the best method would be for OSX. Obviously ActiveX doesn't work on macs...
Any ideas about where to start looking? A flash movie? A firefox add-on? My fingers are tired of googling.
There's no way a vanilla web language will allow you to control peripherals from a webpage under Mac OS.
If you really really need to call that from a webpage and can't afford to make a real application, your best go under Safari would be to build a plugin to use Objective-C from Javascript, and do the heavy-duty work from within your plugin. A similar solution probably exists in Firefox.
Also, as I understand it, your program runs on the client with the printer attached. You could write a server-side script and install it on the Macs, and then have your webpage drive it to do the printing.