参考文件地址：js Promise
Promise术语：
Fulfilled（Resolved）：成功
Rejected：失败
Pending：等待中
Settled：已经成功或已经失败
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Promisify setTimeout</title> </head> <body> <h1>Did the promise finish?</h1> <div class="completion">Not yet</div> <script> function wait(ms) { return new Promise(function(resolve) { console.log(this); window.setTimeout(function() { resolve(); }, ms); }); };
var milliseconds = 2000; wait(milliseconds).then(finish);
function finish() { var completion = document.querySelector('.completion'); completion.innerHTML = "Complete after " + milliseconds + "ms."; }; </script> </body> </html>
