js複製文字

三個API 

1 navigator.clipboard.writeText

2 document.execCommand('copy')

3

document.addEventListener('copy', function(e) {
  // e.clipboardData is initially empty, but we can set it to the
  // data that we want copied onto the clipboard.
  e.clipboardData.setData('text/plain', 'Hello, world!');
  e.clipboardData.setData('text/html', '<b>Hello, world!</b>');

  // This is necessary to prevent the current document selection from
  // being written to the clipboard.
  e.preventDefault();
});

參考：https://stackoverflow.com/questions/400212/how-do-i-copy-to-the-clipboard-in-javascript/30810322#30810322