console 命令行工具 X clear

console

function isObj(obj) {
  return typeof obj === 'object' && 
    Object.prototype.toString.call(obj).toLowerCase() === '[object object]' && 
    !obj.length
}

// 测试promise
// function test(resolve, reject) {
//     var timeOut = Math.random() * 2;
//     console.log('set timeout to: ' + timeOut + ' seconds.');
//     setTimeout(function () {
//         if (timeOut < 1) {
//             console.log('call resolve()...');
//             resolve('200 OK');
//         }
//         else {
//             console.log('call reject()...');
//             reject('timeout in ' + timeOut + ' seconds.');
//         }
//     }, timeOut * 1000);
// }
// var p1 = new Promise(test);
// var p2 = p1.then(function (result) {
//     console.log('成功：' + result);
// });
// var p3 = p2.catch(function (reason) {
//     console.log('失败：' + reason);
// });


// 测试函数
let obj = {"errCode":0,"msg":"Welcome to my-api dev service 1.0...","data":null,"extra":null,"info":{"runTime":"0.00486秒"}}
// console.log(isObj(obj.data))
for(let i in {3}) { 
  alert(i)
}

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8" />
  <title>hehe</title>
</head>
<body>
  这是一个页面
</body>
</html>

body {
  /* background-color: black; */
}