js 复制图片至剪贴板(原生js，可复制word等、不可微信)

copyChart () { // 复制charts为图片
  // 获取highcharts的svg图片
  const img = new Image()
  img.src = `` //图片路径
  // 将svg转化为canvas
  const canvas = document.createElement('canvas')
  const context = canvas.getContext('2d')
  canvas.width = 600
  canvas.height = 400

  const _this = this
  img.onload = function () {
    // svg图加载完毕后绘制到canvas上
    context.drawImage(img, 10, 10)
    // 将canvas转化为png图片
    const imgEle = new Image()
    imgEle.src = canvas.toDataURL('image/png')
    _this.$refs.chartImg.appendChild(imgEle)
    imgEle.onload = function () {
      // 选择图片并复制
      const el = _this.$refs.chartImg.children[0]
      const range = document.createRange()
      const selection = window.getSelection()
      range.selectNode(el)
      selection.removeAllRanges()
      selection.addRange(range)
      document.execCommand('copy')
      selection.removeAllRanges()
      // 复制成功可发送成功message
      el.parentNode.removeChild(el)
    }
  }
}