code: function copyTextToClipboard(text) {
    try {
      // use latest api
      navigator.clipboard.writeText(text);
      return;
    } catch (e) {}
  
    var textArea = document.createElement('textarea'); //
    // *** This styling is an extra step which is likely not required. ***
    //
    // Why is it here? To ensure:
    // 1. the element is able to have focus and selection.
    // 2. if element was to flash render it has minimal visual impact.
    // 3. less flakyness with selection and copying which **might** occur if
    //    the textarea element is not visible.
    //
    // The likelihood is the element won't even render, not even a flash,
    // so some of these are just precautions. However in IE the element
    // is visible whilst the popup box asking the user for permission for
    // the web page to copy to the clipboard.
    //
    // Place in top-left corner of screen regardless of scroll position.
  
    textArea.style.position = 'fixed';
    textArea.style.top = 0;
    textArea.style.left = 0; // Ensure it has a small width and height. Setting to 1px / 1em
    // doesn't work as this gives a negative w/h on some browsers.
  
    textArea.style.width = '2em';
    textArea.style.height = '2em'; // We don't need padding, reducing the size if it does flash render.
  
    textArea.style.padding = 0; // Clean up any borders.
  
    textArea.style.border = 'none';
    textArea.style.outline = 'none';
    textArea.style.boxShadow = 'none'; // Avoid flash of white box if rendered for any reason.
  
    textArea.style.background = 'transparent';
    textArea.value = text;
    document.body.appendChild(textArea);
    textArea.select();
  
    try {
      var successful = document.execCommand('copy');
      var msg = successful ? 'successful' : 'unsuccessful';
      console.log('Copying text command was ' + msg);
    } catch (err) {
      console.log('Oops, unable to copy');
    }
  
    document.body.removeChild(textArea);
  }
docs: 复制文字到剪贴板