Circular Movement Pause?

1

Hi, ive used the Circular Movement Tutorial
http://www.kirupa.com/developer/mx/circular.htm

I want to be able to mouse over the button while its moving and i want it to stop were it is, basically like pauseing the button in its tracks.
Below is the code provided:


onClipEvent (load) {
    var radius = 10 + Math.random() * 50;
    var speed = 5 + Math.random() * 20;
    
    var xcenter = this._x;
    
    var ycenter = this._y;
    
    var degree = 0;
    var radian;
}
onClipEvent (enterFrame) {
    degree += speed;
    radian = (degree/180)*Math.PI;
    this._x = xcenter+Math.cos(radian)*radius;
    this._y = ycenter-Math.sin(radian)*radius;
}

if there is any code i can add to this to get the pauseing effect could someone help.

many thanks in advance

safa.