Problem moving a movie clip

hi!

So that my movie clip does not move progressively with this script?

[COLOR=Magenta]**[COLOR=Purple]my_mc.onrelease = function () {
counter = 0;
while (counter < 100) {
my_mc._x += 1;
counter ++;
}
}[/COLOR]
**[/COLOR]
what does is to locate the object my_mc in the last position. Please help me.