// the "load" event handler is executed only ONCE,

// when the instance first appears on stage

// it is a good place to declare variables

// and set their initial values

onClipEvent (load) {

    var Xincrement = 10; 

}



onClipEvent (enterFrame) {

    // use the variable to change the property

    _x = _x + Xincrement;


    // if the instance goes too far

    // in either direction,

    // change the value of the variable

    if(_x > 300){

        Xincrement = -10;

    } 



    if (_x < 0){

        Xincrement = 10;

    } 


}