The web page includes two frames when you visit http://forum.phy.ntnu.edu.tw/CoLoS/JaCob/index.html
The main page is index.html, it include jacob.html (left frame)and exp.html (right frame)
the right frame changes to expel/EElektrometer.html when you click [u]Electricity[/u]
the right frame changes to expel/EVogal.html when you click [u]Cylinder near conductive corner[/u]
the expel/EVogal.html page will load expel/jco/EVogal.jco when you click [u]setup[/u]
the following is javascript code from expel/EVogal.html
[code]
jint.readExperiment( "expel/jco/EVogal.jco")
[/code]

So you need to have those files in the [b]corresponding subdirectory[/b] to make it work.
Otherwise, you will need to change the html code or javascript code.