How can I send data from a web page to a serial port?

Question

I have a web page which includes a basic content. I can chance its format but it is PHP now. I want to send this data to one of the serial ports of my computer (as a visitor of PHP page).

I need a code for transferring this data from internet to one of the serial-ports. It can be C++, javascript, C# or anything else.

I am using Windows (as a visitor of web page). So, I need to send datas to serial port of visitor's computer not server's. Reading is not necessary.

Which program and process is the best option to do this properly? I need example code parts that they work just fine!