例：是否安装微信

      function isWeixin() {

        var UIApplication = plus.ios.importClass("UIApplication");

        var NSURL = plus.ios.importClass("NSURL");

        var app = UIApplication.sharedApplication();

        var bdScheme = NSURL.URLWithString("baidumap://");

        var install = app.canOpenURL(bdScheme);

        plus.ios.deleteObject(bdScheme);

        plus.ios.deleteObject(app);

      }