javascript - Cannot use `document.execCommand('copy');` from developer console

Question

Calling document.execCommand('copy'); from the Chrome developer console returns false every time.

Give it a try yourself. Open the console and run it, it never succeeds.

Any idea as to why?

Answer 1

document.execCommand('copy') must be triggered by the user. It's not only from the console, it's anywhere that's not inside an event triggered by the user. See below, the click event will return true, but a call without event won't and a call in a dispatched event also.

console.log('no event', document.execCommand('bold'));

document.getElementById('test').addEventListener('click', function(){
    console.log('user click', document.execCommand('copy'));
});

document.getElementById('test').addEventListener('fakeclick', function(){
    console.log('fake click', document.execCommand('copy'));
});


var event = new Event('fakeclick')

document.getElementById('test').dispatchEvent(event) ;

<div id="test">click</ha>