function spriteClip(dom,w,h,time){
	if(dom){
		this.dom = dom;
		this.w = w ||0;
		this.h = h ||0;
		this.time = time || 0;
	}else{
		return false;
	}
}

spriteClip.prototype.run = function(){
	for(var w=0;w<this.w;w++){
		for(var h =0;h<this.h;h++){
			//这里使用闭包以免w,h值随循环改变。
			(function(w,h,self){
				//计算时间
				var time = (h*self.time*self.w+w*self.time);
				setTimeout(function(){
					//计算位置
					self.dom.style.webkitMaskPosition = (100/(self.w-1))*w+'% '+(100/(self.h-1))*h+'%';
				},time);
			})(w,h,this);
		}
	}
}

var sprite1 = document.querySelector('.sprite1');
var sp1 = new spriteClip(sprite1,4,3,50);
sp1.run();

function spriteClip(dom,w,h,time){
	if(dom){
		......
		//记录dom初始的display状态
		this.display = this.dom.style.display;
		//记录动画是否播放过
		this.played = false;
	}else{
		return false;
	}
}
spriteClip.prototype.run = function(){
	//如果动画已经播放过则不做任何动画
	if(this.played)
		return false;
	//标记为已播放完成
	this.played = true;
	//让dom显示
	this.show();
	for(var w=0;w<this.w;w++){
		for(var h =0;h<this.h;h++){
			(function(w,h,self){
				var time = (h*self.time*self.w+w*self.time);
				setTimeout(function(){
					......
					if(w >= self.w-1 && h>=self.h-1){
						//动画结束
						var event = document.createEvent('HTMLEvents');
	                    event.initEvent('finish', true, true);
	                    event.eventType = 'message';
	                    event.content =  'finish';
	                    //触发finish事件
	                    self.dom.dispatchEvent(event);
					}
				},time);
			})(w,h,this);
		}
	}
}
//隐藏dom
spriteClip.prototype.hide = function(){
	this.dom.style.display = 'none';
}
//显示dom
spriteClip.prototype.show = function(){
	this.dom.style.display = this.display;
}
//接收finish时间并用callback函数处理
spriteClip.prototype.finish = function(callback){
	this.dom.addEventListener('finish',callback);
}
var sprite1 = document.querySelector('.sprite1');
var sp1 = new spriteClip(sprite1,4,3,50);
//在做动画之前让sprite隐藏
sp1.hide();
document.addEventListener('touchend',function(){
	//手指抬起后运行动画
	sp1.run();
});
document.addEventListener('click',function(){
	//点击后运行动画
	sp1.run();
});
sp1.finish(function(){
	//动画完成
	console.log('finish');
});