suggestion of further development. I tried to look in the codes but i cannot do it myself.

1. can make it possible to change the direction of the current? it seems to be only downwards for the moment. This can help learners to visualize the effect of the direction of current.

2. can make it obey the
B[sub]perpendicular[/sub] = [sub]o[/sub]I / (2*pi*r)
where
   * [sub]o[/sub], permeability of free space = 4*pi x 10-7 Tm/A
   * I, current flowing through the wire, measured in amps
   * B, magnetic field strength, measured in Tesla
   * r, distance from the wire, measured in meters
http://dev.physicslab.org/Document.aspx?doctype=3&filename=Magnetism_CurrentCarryingWires.xml

3. can add a 3D object of a hand to illustrate the Maxwell's Right Hand Grip Rule?[img]http://www.phy.ntnu.edu.tw/ntnujava/index.php?action=dlattach;topic=181.0;attach=1281;image[/img]


4. Do u want to improve this version? It is yours i think, but the coding is different from the first post's xml.
Reference:
http://www.compadre.org/OSP/document/ServeFile.cfm?ID=8311&DocID=916#Doc916
written by Wolfgang Christian and Fu-Kwun Hwang
technical implementer: Robert Mohr
The EJS Magnetic Field from Loops model computes the B-field created by an electric current through a straight wire, a closed loop, and a solenoid. Users can adjust the vertical position of the slice through the 3D field.
I managed to do a bit here http://www.phy.ntnu.edu.tw/ntnujava/ntnujavazip.php?ejsuserjar=4621&type=xml

For your consideration