Is loadVariablesNum function only can use inside button??

[ssheng27]

Hi.
I have problem with using loadVariablesNum function.
My problem is, i can't use it inside my MC. But it works in my button.

Why i want to put loadVariablesNum function inside my MC, is because i want my MC keep moving once i press "W" key although i had released.

on (keyPress "w"){
_root.x_value= _root.car._x;
_root.y_value= _root.car._y;
loadVariablesNum("http://172.16.218.13:8080/abc/Insert.jsp",0,"post");
}
This coding works. But it only work once. But i would like to let it keep sending the latest position to my database.

Anyone got any suggestion to help me solve this problem??
Thanks a lot..
Thank.....