function timeout(ms){
return new Promise(function(resolve,reject){
setTimeout(resolve,ms);
})
}
async function doSync(){
let time=new Date().getTime();
console.log('等待输出...');
await Promise.all([timeout(5000),timeout(6000)]);
console.log((new Date().getTime()-time)/1000+'秒后输出');
}
doSync();