auto restore viewport

_.js

var autorestore_ = function(element) {
  var oldPosition = element.getBoundingClientRect().bottom
  setTimeout(function() {
    var newPosition = element.getBoundingClientRect().bottom
    window.scrollTo(window.scrollX, window.scrollY + newPosition - oldPosition)
  })
}

__.js

var autorestore_ = function(element, cb) {
  var oldPosition = element.getBoundingClientRect().bottom
  cb(function() {
    var newPosition = element.getBoundingClientRect().bottom
    window.scrollTo(window.scrollX, window.scrollY + newPosition - oldPosition)
  })
}

autorestore_(element, function(restore) {
  manipulate(element)
  restore()
})