var FixHeight = Class.create({
  initialize: function() {
    this.element = $('page');
    this.original_size = this.element.getHeight();
    this.changeHeight();
    Event.observe(window, 'resize', this.changeHeight.bindAsEventListener(this));
  },

  changeHeight: function() {
    var content_height = document.viewport.getHeight() - $('footer').getHeight() - $('header').getHeight() - $('page_content_fade_in').getHeight();
    if (this.original_size < content_height) {
      this.element.setStyle({ height: content_height + 'px' });
    }
  }
});

document.observe('dom:loaded', function() {
  new FixHeight();
});