function createOnePageView(elementClass) {

        var pageView = new ReadiumSDK.Views.OnePageView(options,
        [elementClass],
        false); //enableBookStyleOverrides

        pageView.on(ReadiumSDK.Views.OnePageView.SPINE_ITEM_OPEN_START, function($iframe, spineItem) {

            self.trigger(ReadiumSDK.Events.CONTENT_DOCUMENT_LOAD_START, $iframe, spineItem);
        });   
    
        return pageView;
    }
cfi of the first visible element
@property contentCFI
@type {string}