Is there possible for me to write my program to support plink binary data format?

So far, several libraries support this function, but they are either in C++ or Python. I need a Javascript version, and I couldn't find such an implementation anywhere.

Then I tried to implement my javascript library. However, I need the information about how these binary files are coded, and unfortunately, Plink website does not disclose this information.

Could anyone help a little on this? by either:

1. Point a Javascript library that can read Plink binary file format (This is unlikely to be found since I have been trying for a while. )
2. Or help me point to some instructions about how to write a program to read Plink binary file format. (It seems their official introduction does not disclose this information. )