js 自动复制操作

<button id="btn">copy</button>

var Button = document.getElementById('btn')
Button.addEventListener('click', (event) => {
  let sometext = '内容',
    hiddenInput = document.createElement('input')
  hiddenInput.value = sometext
  hiddenInput.setAttribute('readonly', '')
  hiddenInput.style.position = 'absolute'
  hiddenInput.style.left = '-9999px'
  document.body.appendChild(hiddenInput)
  hiddenInput.select()
  hiddenInput.setSelectionRange(0, hiddenInput.value.length) // ios
  document.execCommand('copy')
  document.body.removeChild(hiddenInput)
  alert('已复制')
})