``` function loadImg(src) { var promise = new Promise(function (resolve, reject) { var img = document.createElement('img') // throw new Error('.....') img.onload = function () { resolve(img) } img.onerror = function () { reject('图片加载失败') } img.src = src }) return promise } ``` ``` // var src = 'https://www.imooc.com/static/img/index/logo_new.png' // var result = loadImg(src) // result.then(function (img) { // console.log(1, img.width) // return img // }).then(function (img) { // console.log(2, img.height) // }).catch(function (ex) { // // 统一捕获异常 // console.log(ex) // }) ```