text: function viewportPosition (win) {
    win = win || window
    var doc = win.document
    var docElem = doc.documentElement || doc.body.parentNode || doc.body
  
    var w = docElem.clientWidth
    var h = docElem.clientHeight
  
    var l = (win.pageXOffset !== undefined)
      ? win.pageXOffset
      : docElem.scrollLeft
  
    var t = (win.pageYOffset !== undefined)
      ? win.pageYOffset
      : docElem.scrollTop
  
    return {
      top: t,
      right: l + w,
      left: l,
      bottom: t + h,
      width: w,
      height: h
    }
  }
  
  module.exports = viewportPosition
  