var urls = ['url','...'], data = []; var buildRequest = function(url) { if (url) { return $.get(url); } }; var request = function() { if (urls && urls.length) { data.push(buildRequest(urls.shift())); data.push(buildRequest(urls.shift())); } if (data.length) { $.when.apply(this,data).then(function(res1,res2){ //TODO }).then(function(){ data = []; request(); }); } }; request();

我一般会这样写

async/await 就是基于 Promise 的，但是更方便：

function run(urls) { let tmp = []; let datas = []; let res = urls.map(async url => { tmp.push(url); if (tmp.length === 2) { let data1 = await getData(tmp[0]); let data2 = await getData(tmp[1]); datas.push(data1, data2); tmp.length = 0; } return datas; }); return res[res.length-1]; } async function getData(url) { let data = await $.get(url); return data; }

使用原生AJAX新API:fetch
不过兼容性不是太好，可以引用兼容库：//cdn.bootcss.com/fetch/2.0.1/fetch.min.js
文档：https://developer.mozilla.org...

示例：

let urls = [ 'http://api.hitokoto.cn/?c=a', 'http://api.hitokoto.cn/?c=a', 'http://api.hitokoto.cn/?c=a', 'http://api.hitokoto.cn/?c=a', 'http://api.hitokoto.cn/?c=a', ] function getJSON(url) { return fetch(url).then(res => res.json()) } getJSON(urls[0]) .then(json => { console.log(+new Date()) console.info(json); return getJSON(urls[1]) }) .then(json => { console.log(+new Date()) console.info(json); return getJSON(urls[2]) }) // 如果不介意用 babel 转码的话，可以使用 async / await // 还需要引入垫片 http://cdn.bootcss.com/babel-polyfill/6.13.0/polyfill.min.js // 示例： let sleep = ms => new Promise(resolve => setTimeout(resolve, ms)) (async () => { for (let url of urls) { await sleep(1000) // 等待 1000 毫秒再执行下面语句 let json = await getJSON(url) // 等待结果返回再执行下面语句 console.log(+new Date()) console.info(json) } })()

这样是不是可以？

var urls = []; var results = []; for(let i = 0 ; i < 5 ; i ++){ var url1 = urls[2*i]; var url2 = urls[2*i + 1]; var p = new Promise(function(resolve,reject){ ajax(url1,function(res1){ resolve(res1); }) }); var q = new Promise(function(resolve,reject){ ajax(url2,function(res2){ resolve(res2); }) }); Promise.all([p,q]).then(function(data){ results[2*i] = data[0]; results[2*i + 1] = data[1]; }); }