fix_fixed.coffee

fix_fixed.coffee

define [
  'jquery'
], ($) ->

  # Fix Fixed is a work around an iOS bug involving fixed positioned elements.
  # Whenever the keyboard shows up, a fixed positioned element would reposition
  # itself randomly on the screen. This work around adds the .fix-fixed class to the
  # body in order to let fixed positioned elements change their position to absolute
  # while the keyboard is shown.
  #
  # The solution presented here is used: http://dansajin.com/2012/12/07/fix-position-fixed/
  # + the scroll hack.

  if Modernizr.ios
    $body = $('body')

    $(document)
    .on 'focus', 'input, textarea', (e) ->
      $body.addClass('fix-fixed')
    .on 'blur', 'input, textarea', (e) ->
      $body.removeClass('fix-fixed')
      _.defer scrollFix

    scrollFix = ->
      # Sometimes the fix positioned element requires a scroll before it returns to its place.
      # Some solutions use $(window).scrollTop(0), but that would actually change the expected
      # position on the screen. This solution performs a scroll of only 1 pixel.
      $(window).scrollTop(window.scrollY + 1)