var imgs=["img1","img2","img3","img4","img5"];
				//  0       1        2        3       4
	var deletes=imgs.splice(0,2);删除img1和img2,0开始的2个
	imgs=imgs.concat(deletes);//将删除的img1和img2连接到img5后面
	console.log(String(imgs));//img3,img4,img5,img1,img2