You can test your mark-up in mobile browser, this is a good quick test for your mark-up and can be very useful for debugging, although all mark-up should be thoroughly tested in Pugpig too. Using the browser on the device is a good litmus test for the device capability - especially if you are creating stand alone HTML pages, such as Creating Ad Pages for Pugpig /bespoke pages.
Read more about Apple's guidelines around HTML for iOS
As mobile devices do not always have a huge amount of memory, you need to ensure your page (especially your adverts) do not use too much. A good way to test this is to view the pages directly in the mobile browser (for example, Mobile Safari on iOS). If your advert crashes the browser, it is likely to also crash your Pugpig app. Always test on the lowest spec device you are supporting. For iOS, for example, test on an iPad 1.