Viewport argument key "viewport-fit" not recognized and ignored.

[RicoLiu]

问题：
在 iOS 10 上报错：

Viewport argument key "viewport-fit" not recognized and ignored.

google 了一下发现是因为适配 iPhoneX 的刘海屏而导致的，这样的话，就需要对 iOS 11 做兼容性处理了。

解决：

    (function () {
      var viewportTag = null;
      var metaTags = document.getElementsByTagName('meta');
      for (var i = 0; i < metaTags.length; i++) {
          if (metaTags[i].getAttribute('name') === "viewport") {
              viewportTag = metaTags[i];
              break;
          }
      }
      if (!viewportTag) {
          viewportTag = document.createElement("meta");
          viewportTag.setAttribute('name', 'viewport');
      }
      
      var viewportTagContent = 'width=device-width, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0, user-scalable=0';
      
      // Detect if iOS device
      if (/(iPhone|iPod|iPad)/i.test(window.navigator.userAgent)) {
        // Get iOS major version
        var iosVersion = parseInt((window.navigator.userAgent).match(/OS (\d+)_(\d+)_?(\d+)? like Mac OS X/i)[1]);
        // Detect if device is running >iOS 11
        // iOS 11's UIWebView and WKWebView changes the viewport behaviour to render viewport without the status bar. Need to override with "viewport-fit: cover" to include the status bar.
        if (iosVersion >= 11) {
          viewportTagContent += ', viewport-fit=cover';
        }
      }
      
      // Update viewport tag attribute
      viewportTag.setAttribute('content', viewportTagContent);
    })()

参考引用：mapsplugin/cordova-plugin-googlemaps#1645