copy string to your clipboard by javascript

copyToClipboard.js

function copyToClipboard(str) {
    if (!str) {
        return;
    }
    // input element cannot keep '\n', so you can turn to textarea
    const inputEl = document.createElement('textarea');
    inputEl.value = str;
    inputEl.style.cssText = 'position: absolute; top: -9999px; left: -9999px;';
    document.body.appendChild(inputEl);
    inputEl.select();
    inputEl.setSelectionRange(0, 99999);
    document.execCommand('copy');
    document.body.removeChild(inputEl);
}