JS實現頁面複製文字時自動加版權

經親自實踐，嘗試了各類方法，目前可行的方法主要有以下兩種：
能夠在任何運行使用js代碼的網站中使用，好比本人在本身的博客園博客中實現了一下，讀者您可親自在本人博客上測試。

方法1：

<script language="javascript" type="text/javascript">
jQuery(document).on('copy', function(e)
    {
      var selected = window.getSelection();
      var selectedText = selected.toString().replace(/\n/g, '<br>');  // Solve the line breaks conversion issue
      var pageInfo = '<br>---------------------<br>著做權歸做者全部。<br>' 
                            + '商業轉載請聯繫做者得到受權，非商業轉載請註明出處。<br>'
                            + '做者：Bravo Yeung<br> 源地址：' + document.location.href
                            + '<br>來源：博客園cnblogs<br>© 版權聲明：本文爲博主原創文章，轉載請附上博文連接！';
      var copyHolder = $('<div>', {id: 'temp', html: selectedText + pageInfo, style: {position: 'absolute', left: '-99999px'}});
        
      $('body').append(copyHolder);
      selected.selectAllChildren( copyHolder[0] );
      window.setTimeout(function() {
          copyHolder.remove();
      },0);
    });
</script>

方法2:

<script type="text/javascript">
    var ua = navigator.userAgent.toLowerCase();
    if (window.ActiveXObject) {  /* 兼容舊版的IE */
        document.body.oncopy = function () {
            event.returnValue = false;
            var selectedText = document.selection.createRange().text;
            var pageInfo = '<br>---------------------<br>著做權歸做者全部。<br>'
                + '商業轉載請聯繫做者得到受權，非商業轉載請註明出處。<br>'
                + '做者：Bravo Yeung<br> 源地址：' + document.location.href
                + '<br>來源：博客園cnblogs<br>© 版權聲明：本文爲博主原創文章，轉載請附上博文連接！';
            clipboardData.setData('Text', selectedText.replace(/\n/g, '<br>') + pageInfo);
        }
    }
    else {
        function addCopyRight() {
            var body_element = document.getElementsByTagName('body')[0];
            var selection = window.getSelection();
            var pageInfo = '<br>---------------------<br>著做權歸做者全部。<br>'
                + '商業轉載請聯繫做者得到受權，非商業轉載請註明出處。<br>'
                + '做者：Bravo Yeung<br> 源地址：' + document.location.href
                + '<br>來源：博客園cnblogs<br>© 版權聲明：本文爲博主原創文章，轉載請附上博文連接！';
            var copyText = selection.toString().replace(/\n/g, '<br>') + pageInfo;  // Solve the line breaks conversion issue
            var newDiv = document.createElement('div');
            newDiv.style.position = 'absolute';
            newDiv.style.left = '-99999px';
            body_element.appendChild(newDiv);
            newDiv.innerHTML = copyText;
            selection.selectAllChildren(newDiv);
            window.setTimeout(function () {
                body_element.removeChild(newDiv);
            }, 0);
        }
        document.oncopy = addCopyRight;
    }
</script>

方法3:

<script  type="text/javascript">
    var selfLogin = false;
    var follow = $('#profile_block').find('#p_b_follow');
    var block = follow.length >= 1 ? follow[0] : "";
    var followText = (block != null && block != undefined) ? block.innerHTML : "";
    if(followText == "") selfLogin = true;

    var pageInfo = '\r\n---------------------\r\n著做權歸做者全部。\r\n'
        + '商業轉載請聯繫做者得到受權，非商業轉載請註明出處。\r\n'
        + '做者：Bravo Yeung\r\n源地址：' + document.location.href
        + '\r\n來源：博客園cnblogs\r\n© 版權聲明：本文爲博主原創文章，轉載請附上博文連接！';

    document.addEventListener('copy', function (ev) {
        var targetHTML = $.trim($(ev.target).html());
        // console.log("targetHTML:" + targetHTML)
        if (targetHTML == "") return;
        if (!(targetHTML.startsWith('<table class="hljs-ln"') && targetHTML.endsWith('</table>')) || !selfLogin)  // isLogined
        {
            var selected = window.getSelection();
            var selectedText = selected.toString();  
            let copyRightStr = (selectedText + pageInfo).replace(/\n/g, '\r\n'); // Solve the line breaks conversion issue

            ev.clipboardData.setData('text/plain', `${copyRightStr}`);
            ev.preventDefault();
        }
    });
</script>

目前本人博客使用了方法3.

方法1 最初發表在本人的博客園文章中：
https://www.cnblogs.com/enjoy233/p/10328361.html#複製正文文字時自動加版權
https://segmentfault.com/q/1010000003986612/a-1020000018332118/