Adding a mouse event into a script (rotator menu)

I am creating a rotating menu. This is the code in each one of the 4 buttons inside the menu.

PHP Code:

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onClipEvent(load){
    y=0;
    speedR=5;
    radius=100;
    xcenter=393/2;
    ycenter=325/2;
    zcenter=100;
    angle=0;
    fl=150;
    }

    onClipEvent(enterFrame){
    _x=Math.cos(angle*Math.PI/180)*radius+xcenter;
    _y=y+ycenter;
    z=Math.sin(angle*Math.PI/180)*radius+zcenter;
    scale=fl/(fl+z);
    _xscale= _yscale = scale*100;
    angle+=speedR;
    if(angle>359){
    angle-=360;
    }

    } 


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How can I add a mouse event in which slows down the speed of the button or stop the menu of moving??

Thank you

On main timeline...

Code:

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var isOver = false;

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On clips...

Code:

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onClipEvent (load) {
        y = 0;
        speedR = 5;
        radius = 100;
        xcenter = 393 / 2;
        ycenter = 325 / 2;
        zcenter = 100;
        angle = 0;
        fl = 150;
        this.onRollOver = function() {
                _root.isOver = true;
        };
        this.onRollOut = function() {
                _root.isOver = false;
        };
}
onClipEvent (enterFrame) {
        _x = Math.cos(angle * Math.PI / 180) * radius + xcenter;
        _y = y + ycenter;
        z = Math.sin(angle * Math.PI / 180) * radius + zcenter;
        scale = fl / (fl + z);
        _xscale = _yscale = scale * 100;
        angle += ((_root.isOver) ? 0.5 : speedR);
        if (angle > 359) {
                angle -= 360;
        }
}

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