Key.isDown to be used in a button

[dawsonk]

Perhaps this will give you some ideas...

// added two background movie clips to the stage,
// instance names bgA and bgB, both must be wider than stage

var dy:Number = 0;
var gravity:Number = 1;
var canjump:Boolean = false;
var minObj:int = 2;
var maxObj:int = 5;
var objs:Sprite = new Sprite();
var hurdle:Hurdle;
var healthAmt:int = 10;
var maxHealth:int = health.width;

hero.gotoAndStop('still');
hero.upval = 0;
bgA.speed = 5;
bgA.x = 0;
bgB.x = bgA.x + bgA.width;
addObj(bgB);

btnPause.addEventListener(MouseEvent.MOUSE_DOWN, doPause);
btnJump.addEventListener(MouseEvent.MOUSE_DOWN, doJump);
stage.addEventListener(MouseEvent.MOUSE_UP, doWalk);
stage.addEventListener(Event.ENTER_FRAME,onenter);

function doPause(e:Event):void {
        bgA.speed = 0;
        hero.scaleX = -1;
        hero.gotoAndStop('still');
}
function doJump(e:Event):void {
        hero.upval = -20;
}
function doWalk(e:Event):void {
        hero.upval = 0;
        bgA.speed = 5;
        hero.gotoAndStop('walking');
}
function onenter(e:Event):void {
        bgA.x -=  bgA.speed;
        bgB.x -=  bgA.speed;
        if (bgA.x <  -  bgA.width) {
                bgA.x = bgB.x + bgB.width;
                addObj(bgA);
        }
        if (bgB.x <  -  bgB.width) {
                bgB.x = bgA.x + bgA.width;
                addObj(bgB);
        }
        dy +=  gravity;
        if (hero.y > 300) {
                dy = 0;
                canjump = true;
        }
        if (canjump) {
                dy = hero.upval;
                canjump = false;
        }
        hero.y +=  dy;
        if (hero.hitTestObject(bgA)) {
                checkHit(bgA);
        }
        if (hero.hitTestObject(bgB)) {
                checkHit(bgB);
        }
}
function checkHit($mc:MovieClip):void {
        objs = $mc.getChildByName($mc.name) as Sprite;
        if (objs) {
                for (var i:int; i < objs.numChildren; i++) {
                        hurdle = (objs.getChildAt(i)) as Hurdle;
                        if (! hurdle.gotHit) {
                                if (hero.hitTestObject(hurdle)) {
                                        hurdle.gotHit = true;
                                        health.width -= (maxHealth / healthAmt);
                                        if (health.width <= 0){
                                                trace("game over");
                                                stage.removeEventListener(Event.ENTER_FRAME,onenter);
                                        }
                                }
                        }
                }
        }
}
function addObj($mc:MovieClip):void {
        objs = $mc.getChildByName($mc.name) as Sprite;
        if (objs) {
                $mc.removeChild(objs);
        }
        objs = new Sprite();
        objs.name = $mc.name;
        var numObj:int = randomRange(minObj,maxObj);
        for (var i:int = 0; i < numObj; i++) {
                hurdle = new Hurdle();
                hurdle.x = randomRange(hurdle.width,$mc.width - hurdle.width);
                hurdle.y = 300 - hurdle.height;
                objs.addChild(hurdle);
        }
        $mc.addChild(objs);
}
function randomRange(min:Number, max:Number):Number {
        return (min + Math.random() * (max - min));
}