js监听浏览器剪贴板

function setClipboardText(event){
      event.preventDefault();
      var node = document.createElement('div');
      node.innerHTML= window.getSelection(0).toString();
      var result = window.getSelection(0).toString();
      if (result.length>51){
                result=result.substring(0,50);
      }
      var htmlData = '<div>此版权归所XXXXX所有。<br />'
                      + '如有它用请联系XXXXXXX获得授权。<br />'                      
                      + '来源：XXXXXXXX<br /><br />'
                      + '每次复制最多50个字<br /><br />'
                      + result
                      + '</div>';
      var textData = '此版权归所XXXXXX所有。\n'
                      + '如有它用请联系XXXXXXXX获得授权。\n'
                      + '每次复制最多50个字\n'
                      + result;
      if(event.clipboardData){
          event.clipboardData.setData("text/html", htmlData);
          event.clipboardData.setData('text/plain', textData);
      }
      else if(window.clipboardData){
          return window.clipboardData.setData("text", textData);
      }
};

document.addEventListener('copy', function(event){
setClipboardText(event);
});