let p =['http://img3.imgtn.bdimg.com/it/u=3278834702,2663618759&fm=26&gp=0.jpg','http://img5.imgtn.bdimg.com/it/u=4180508012,1972588723&fm=15&gp=0.jpg','http://img10.360buyimg.com/n1/s350x449_jfs/t14989/169/1956143206/90455/a454f42c/5a657289N4b6344d4.jpg%21cc_350x449.jpg','http://b-ssl.duitang.com/uploads/item/201707/24/20170724135526_FCnkr.thumb.700_0.jpeg'];
function createImg(url){returnnewPromise((resolve, reject)=>{setTimeout(()=>{
let img =newImage();
img.src = url;
document.body.append(img)
img.onload =()=>{resolve(img)}
img.onerror =()=>{reject("加載失敗")}},1000)})}
# forEach代碼
p.forEach(async (item)=>{
await createImg(item)})
for循壞代碼
async function run(){for(let i =0; i < p.length; i++){
await createImg(p[i])}}run(