请求发送通知的权限

我们使用 Notification.requestPermission 询问用户是否希望从我们的网站接收通知。

Notification.requestPermission(function() {
    if (Notification.permission === 'granted') {
        // user approved.
        // use of new Notification(...) syntax will now be successful
    } else if (Notification.permission === 'denied') {
        // user denied.
    } else { // Notification.permission === 'default'
        // user didn’t make a decision.
        // You can’t send notifications until they grant permission.
    }
});

从 Firefox 47 开始，.requestPermission 方法在处理用户授予权限的决定时也可以返回一个承诺

Notification.requestPermission().then(function(permission) {
    if (!('permission' in Notification)) {
        Notification.permission = permission;
    }
    // you got permission !
    }, function(rejection) {
    // handle rejection here.
    }
);