在网页运行没有错误， 但编译运行ios版本时出现body is null错误，导致无法运行：
cocos2d: fullPathForFilename: No file found at script/jsb_prepare.jsc. Possible missing file.
cocos2d: fullPathForFilename: No file found at script/jsb_boot.jsc. Possible missing file.
JS: Cocos2d-JS v3.13
(evaluatedOK == JS_FALSE)
JS: /Users/q/Library/Developer/CoreSimulator/Devices/B2CDA198-FCB0-4E04-B9D5-6A3A0F93C4BF/data/Containers/Bundle/Application/9FEBE876-DAB6-429E-83A6-C4C171C7E788/
Tank-mobile.app/script/physicsSprite/jsb_physicsSprite.js:51:TypeError: body is null
Evaluating main.js failed (evaluatedOK == JS_FALSE)
2016-11-17 16:15:29.843 Tank-mobile[33112:552538] cocos2d: surface size: 1136x640
cocos2d: QuadCommand: resizing index size from [-1] to [2560]
2016-11-17 16:15:29.865 Tank-mobile[33112:552538] cocos2d: surface size: 1136x640
代码：
var Bullet = cc.PhysicsSprite.extend({
attack:100,
type:"bullet",
uid:0,
speed:10,
phyBody:null,
shape:null,
world:null,
isDead:false,
ctor:function (target, pos,uid) {
this._super();
cc.log("create bullet ");
this.world = target;
this.uid = uid;
this.initWithSpriteFrameName("bullet.png" );
this.setAnchorPoint(0.5,0.5);
var radius = this.getContentSize().width/2;
mass = 2;
this.phyBody = target.space.addBody(new cp.Body(mass, cp.momentForCircle(mass, 0, radius, cp.v(0, 0))));
this.phyBody.owner = this;
this.phyBody.setPos(pos);
this.shape = new cp.CircleShape(this.phyBody, radius, cp.v(0, 0));
var circle = target.space.addShape(this.shape);
circle.setElasticity(1);
circle.setFriction(0);
circle.setCollisionType(collisions.COLLISIONS_TYPE_BULLET);
this.body = this.phyBody;
this.setBody( this.phyBody );
return this;
},