js的复制文本功能-复制到黏贴板

    static copyToClipboard = (str: string): void => {
        const el = document.createElement('textarea');
        el.value = str;
        el.setAttribute('readonly', '');
        el.style.position = 'absolute';
        el.style.left = '-9999px';
        document.body.appendChild(el);
        const selected =
            document.getSelection().rangeCount > 0
            ? document.getSelection().getRangeAt(0)
            : false;
        el.select();
        document.execCommand('copy');
        document.body.removeChild(el);
        if (selected) {
            document.getSelection().removeAllRanges();
            document.getSelection().addRange(selected);
        }
        successTip("复制成功");
    };