Moving from Flash to HTML5/CSS/ etc

Some years ago I decided I could bypass all the browser inconsistencies by producing sites entirely in Flash. Doesn't look such a good decision now so I'm re-writing my semi-CMS framework in php, javascript/jQuery and HTML. One aspect of my Flash sites which I am very pleased with is the ability to 开发者_运维技巧load all pages or states in the background so the user rarely requests a page that isn't already loaded. When that does happen I can display a progress bar. In AJAX I can't display progress but I also found a significant difference I hadn't anticipated. In Flash I load the .swf for page 1 completely, before starting to load page 2. That means everything including images etc. In AJAX I can't see a way to do that. I can check that the HTML file itself has completed loading, but not that all its images have loaded before loading the next HTML file. Is it possible?

If you're looking for an HTML5 solution rather than just an AJAX solution you might want to investigate the Application Cache. There is a progress event which you could hook into, though it possibly doesn't get into the level of detail you need. As far as I'm aware, resources will start downloading in the order they're listed in the manifest file.