onClipEvent(load ){

    // initialize the Xtarget variable

    // and set it to a random number 

    // between 0 and 300

    var Xtarget = random(301); 

}


onClipEvent(enterFrame ){

    // if the horizontal position of the instance

    // is to the right (greater than) the target value, 

    // then move it to the left one pixel. 

    // if the instance is to the left (less than) the target value, 

    // then move it to the right.

    // if the instance is at (equal to) the target value,

    // make a new target value.

    if(_x > Xtarget){

        _x = _x - 1;

    } else if (_x < Xtarget){

        _x = _x + 1;

    } else {

        Xtarget = random(301); 
    } 



}