Question

我正在尝试使用https://github.com/matthewhudson/current-device

在演示页https://thematthewhudson.com/current-device/上，我查看了页面的源代码，我看到了：

https://thematthewhudson.com/current-device/

<script src="https://unpkg.com/current-device/umd/current-device.min.js"></script>
<script type="text/javascript">
      var device = device.default;

      console.log("device.portrait() === %s", device.portrait());
      console.log("device.landscape() === %s", device.landscape());
      console.log("device.mobile() === %s", device.mobile());
      console.log("device.tablet() === %s", device.tablet());
      console.log("device.ipad() === %s", device.ipad());
      console.log("device.ipod() === %s", device.ipod());
      console.log("device.iphone() === %s", device.iphone());
      console.log("device.android() === %s", device.android());
      console.log("device.androidTablet() === %s", device.androidTablet());
      console.log("device.blackberryTablet() === %s", device.blackberryTablet());
      console.log("device.fxos() === %s", device.fxos());
      console.log("device.fxosPhone() === %s", device.fxosPhone());
      console.log("device.fxosTablet() === %s", device.fxosTablet());
      console.log("device.meego() === %s", device.meego());
      console.log("device.television() === %s", device.television());

      device.onChangeOrientation(function (newOrientation) {
        console.log("New orientation is " + newOrientation);
      });
    </script>

当我做同样的事情时：

我在控制台上收到此错误：

Uncaught TypeError: Cannot read property 'default' of undefined
at window.onload (fiddle.jshell.net/:206)

这是我所做的例子的小提琴：

https://jsfiddle.net/52g75e2s/5/

为什么我收到此未定义的错误？

是因为var device = device.default;吗？

Answer 1

这是一个非常小的脏HTML页面。将其保存在文件中并在浏览器中打开。看看控制台（没有其他输出）

<html>
  <head>
  </head>
  <body>
  <script src="https://unpkg.com/current-device/umd/current-device.min.js"></script>
  <script type="text/javascript">
      var device = device.default;

      console.log("device.portrait() === %s", device.portrait());
      console.log("device.landscape() === %s", device.landscape());
      console.log("device.mobile() === %s", device.mobile());
      console.log("device.tablet() === %s", device.tablet());
      console.log("device.ipad() === %s", device.ipad());
      console.log("device.ipod() === %s", device.ipod());
      console.log("device.iphone() === %s", device.iphone());
      console.log("device.android() === %s", device.android());
      console.log("device.androidTablet() === %s", device.androidTablet());
      console.log("device.blackberryTablet() === %s", device.blackberryTablet());
      console.log("device.fxos() === %s", device.fxos());
      console.log("device.fxosPhone() === %s", device.fxosPhone());
      console.log("device.fxosTablet() === %s", device.fxosTablet());
      console.log("device.meego() === %s", device.meego());
      console.log("device.television() === %s", device.television());

      device.onChangeOrientation(function (newOrientation) {
        console.log("New orientation is " + newOrientation);
      });
    </script>
  </body>
</html>

为什么我得到一个未定义的错误？

1 个答案: