import flash.geom.Point;

import flash.display.MovieClip;

import flash.display.Graphics;

var mc:MovieClip=new MovieClip();

addChild(mc);

drawDashed(mc,new Point(100,100),new Point(500,100),5,5);

function drawDashed(mc:Sprite,p1:Point,p2:Point,length:Number=5,gap:Number=5):void

{

    var max:Number = Point.distance(p1,p2);

    var len:Number = 0;

    var p3:Point;

    var p4:Point;

    while(len<max)

    {

        p3 = Point.interpolate(p2,p1,len/max);

        len+=length;

        if(len>max)len=max

        p4 = Point.interpolate(p2,p1,len/max);

        mc.graphics.lineStyle(1,0xff00ff,1)

           mc.graphics.moveTo(p3.x,p3.y)

        mc.graphics.lineTo(p4.x,p4.y)

        len+=gap;

    }

}