Wrap $viewport option in views with a jquery call so it can accept multiple input types (selector, native element, jquery element itself, etc)
MODIFY
js/views/fixed_view.js
js/views/fixed_view.js
@@ -40,7 +40,7 @@ var FixedView = function(options, reader){
var self = this;
var _$el;
- var _$viewport = options.$viewport;
+ var _$viewport = $(options.$viewport);
var _spine = options.spine;
var _userStyles = options.userStyles;
var _bookStyles = options.bookStyles;

MODIFY
js/views/reflowable_view.js
js/views/reflowable_view.js
@@ -42,7 +42,7 @@ var ReflowableView = function(options, reader){
var self = this;
- var _$viewport = options.$viewport;
+ var _$viewport = $(options.$viewport);
var _spine = options.spine;
var _userStyles = options.userStyles;
var _bookStyles = options.bookStyles;

MODIFY
js/views/scroll_view.js
js/views/scroll_view.js
@@ -59,7 +59,7 @@ var ScrollView = function (options, isContinuousScroll, reader) {
var self = this;
- var _$viewport = options.$viewport;
+ var _$viewport = $(options.$viewport);
var _spine = options.spine;
var _userStyles = options.userStyles;
var _deferredPageRequest;

Wrap $viewport option in views with a jquery call so it can accept multiple input types (selector, native element, jquery element itself, etc)