Flash as continuous scrolling picture effect

The idea of a picture effect is to append a picture beyond the visual range to the end of the last picture or to a position in the stage. As long as you can follow the last picture in the back of the line.
For (I=1 i<7; i++) {
This.createemptymovieclip ("MC" +i, I)//create a blank movie (in fact, there is I, so that the movement of each MC will not affect other MC movement.)
This["MC" +i]._x = 10;
This["MC" +i]._y = (i-1) *100+20;//set the location of its x,y
This["MC" +i].attachmovie ("M" +i, "MC" +i, 7*i);/Load Internal MC
This["MC" +i].onenterframe = function () {//Add a Enterframe event
This._y = this._y-2;//Let every film loaded with MC be in motion
if (this._y<-128) {//Determine whether the position of the movie has reached the specified location, if it arrives, execute the following statement.
This._y = stage.height+80;//The Y-position of the MC with the bounds set to Stage height
}
};
}