Communication between RS422 serial device and Javascript

Question

Hi,

I've written a simple web page that uses Javascript to control a Quicktime plugin for movie playback. There's also some AJAX stuff using jquery to get info on the movies from an MSSQL database. The web page is served to the user from an Apache 2.0 server, this also hosts MSSQL. The end users will view the page in IE6 (unfortunately).

My problem is that the end users now want to use an RS422 jog/shuttle deck control to drive the movie timeline, in place of another jog/shuttle unit that relied on emulating keypresses which was easy for me to detect.

As I'm not a programmer I'm at a loss what to start looking at for a solution to receive the RS422 data and then send that to the Javascript to control the timeline. Is this something that a custom activeX bit of code could do? I've googled ActiveX with Javascript but it's unclear to me (as a novice) how the two work together, or whether this would be suitable at all.

If anyone could give me an overview of what to start researching that'd be much appreciated.

Many thanks.

Jon

Answer 1

JavaScript runs in a sandbox and has no access to the computer at all (for security reasons; you really don't want to make it any more simple for frauds to get at your credit card data).

ActiveX would work but it's a security risk, too. ActiveX is written in C++, no JavaScript there. You'll find information about that on the M$ Website. Note that ActiveX is usually disabled today because of said security risks. Depending how serious your client take security, the virus scanner might not allow to start an A/X control.

Another option would be to write small program which is installed on the client's computer that reads the serial port and send that to the web server where your JavaScript can query it. Okay, that's more than a bit convoluted but probably the least risky.

Or you write a program which transforms the serial codes into key presses (just create the event and post it to Windows). Again, you need C++ or maybe Python with the win32 package.

Your client must understand that this is something which sounds incredibly simple but you'll have to jump through a lot of hoops to make it work. A web browser is not a local application with full reign of the hardware (and it must never be).