Why do you use a cache manifest? Normally, with a Cordova/Phonegap project, your files will be included in the project, and reside on the local device filesystem. Not on your server.
BTW, you have some invalid HTML. It's clearly shown in red in the Fiddle. You should use use &, not & to display an ampersand.
datesandtimes.html will not be loaded from your server! The origin of a Cordova/Phonegap site is the local filesystem in the device, not your server. If you mean to load it from your server, you need to prepend your website. e.g. example.com/datesandtimes.html.
It's a bit odd to use an Ajax call to populate page content. But since you use a multi-page, I can understand why you did it, because JQM isn't designed to mix single-page and multi-page. Really, I don't recommend ever using a multi-page document, unless you have a VERY small site (e.g. a handful of pages).
You can't use simple pagebeforeshow to solve this. The page will probably show before the response is ever received.
You will need to use a pagecontainer widget beforeload callback. The page change will be deferred until you resolve the deferred provided in the beforeload callback. When your Ajax callback has been called, and you have inserted the content into the page, then you can resolve deferred, and processing of the page will continue.