// 判断是否IE<11浏览器
export function isIE () {
  return navigator.userAgent.indexOf('compatible') > -1 && navigator.userAgent.indexOf('MSIE') > -1
}

export function isIE11 () {
  return navigator.userAgent.indexOf('Trident') > -1 && navigator.userAgent.indexOf('rv:11.0') > -1
}

// 判断是否IE的Edge浏览器
export function isEdge () {
  return navigator.userAgent.indexOf('Edge') > -1 && !isIE()
}

export function getIEVersion () {
  const userAgent = navigator.userAgent // 取得浏览器的userAgent字符串
  const isIEFlag = isIE()
  const isIE11Flag = isIE11()
  const isEdgeFlag = isEdge()

  if (isIEFlag) {
    const reIE = new RegExp('MSIE (\\d+\\.\\d+);')
    reIE.test(userAgent)
    const fIEVersion = parseFloat(RegExp.$1)
    if (fIEVersion === 7 || fIEVersion === 8 || fIEVersion === 9 || fIEVersion === 10) {
      return fIEVersion
    } else {
      return 6// IE版本<7
    }
  } else if (isEdgeFlag) {
    return 'edge'
  } else if (isIE11Flag) {
    return 11
  } else {
    return -1
  }
}