navigator.clipboard is undefined

问题:

Why is navigator.clipboard always undefined in the following snippet?

var clipboard = navigator.clipboard;
if (clipboard == undefined) {
    console.log('clipboard is undefined');
} else {
    clipboard.writeText('stuff to write').then(function() {
        console.log('Copied to clipboard successfully!');
    }, function() {
        console.error('Unable to write to clipboard. :-(');
    });
}

More on the clipboard API can be found here.

Chrome Version: 68.0.3440.106.

I'm sure this was working at some point, but no longer is. It's confusing because this table suggests that the Clipboard API is implemented in Chrome (has been for some time), but this table of specific API methods suggests that none of the methods of the API is supported??

回答1:

This requires a secure origin — either HTTPS or localhost (or disabled by running Chrome with a flag). Just like for ServiceWorker, this state is indicated by the presence or absence of the property on the navigator object.

https://developers.google.com/web/updates/2018/03/clipboardapi

This is noted in the spec with [SecureContext] on the interface: https://w3c.github.io/clipboard-apis/#dom-navigator-clipboard

You can check the state of window.isSecureContext to learn if that's the reason a feature is unavailable. Secure contexts | MDN

And yes, you should set up HSTS to make sure HTTP redirects to HTTPS.