How can I copy text in one click in Mozilla Firefox?

Question

This code works fine in Google Chrome, Opera, IE 11. But it doesn\'t work in Mozilla firefox and Safari. I get error in the following string \"var successful = document.exec

Answer 1

As of Firefox 41 (September 2015) the copy command should be available by default when triggered from certain trusted (user-triggered) events, such as what would be fired in response to a button click. The compatibility table from MDN offers further information, see also the release notes.

The code in the question should therefore work. Indeed, I tested something very similar (see code below) and it worked great for me using Firefox 44.

function doCopy() {
    var textToCopy = document.getElementById('textToCopy');
    var range = document.createRange();
    range.selectNodeContents(textToCopy);
    window.getSelection().addRange(range);
    document.execCommand('copy');
}

(function() {
    var el = document.getElementById("copyTrigger");
    el.addEventListener("click", doCopy, false);
})();

textarea {display: block; margin-top: 1em; width: 500px;}

<div id="textToCopy">Elephant</div>
<button id="copyTrigger">Copy above text</button>
<textarea placeholder="Try pasting here to test"></textarea>