Open centered popup window

openPopupWin.js

// open with html string
function openPopupWin (content, width, height) {
  var w = innerWidth || document.documentElement.clientWidth || screen.width
  var h = innerHeight || document.documentElement.clientHeight || screen.height
  var position = 'scrollbars=yes,width=' + width + ',height=' + height
  position += ',top=' + ((h - height) / 2 + screenTop || screen.top || 0)
  position += ',left=' + ((w - width) / 2 + screenLeft || screen.left || 0)
  var popupWin = window.open('about:blank', '', position)

  popupWin.document.write(content)

  if (window.focus) popupWin.focus()
}

// open url with a title
function openPopupWin (url, title, width, height) {
  var w = innerWidth || document.documentElement.clientWidth || screen.width
  var h = innerHeight || document.documentElement.clientHeight || screen.height
  var position = 'scrollbars=yes,width=' + width + ',height=' + height
  position += ',top=' + ((h - height) / 2 + screenTop || screen.top || 0)
  position += ',left=' + ((w - width) / 2 + screenLeft || screen.left || 0)
  var popupWin = open(url, title, position)

  if (focus) popupWin.focus()
}