CreateJS PreLoadJSPreLoadJS is a JavaScript library to help you with asset preload management. It’s part of CreateJS an open source suite of JavaScript libraries to help HTML5 developers

When you build a great web site, you need to plan your asset loading so that users don’t get frustrated and leave your website. When you build Windows 8 apps, loading assets is something you have to consider carefully because to publish an app to the Windows 8 store, your app must launch in 5 seconds or less on a low-power computer according to certification requirement 3.8. Asynchronous code is always a good strategy, so is displaying your own splash screen and showing a progress bar as your assets load so the user understands that the program is running and your app is loading assets.

If you are working with HTML5 and JavaScript, you might as well take advantage of the functions in the PreLoadJS library to make your life a little easier. This library can be used for both Windows 8 and Web development.

The PreLoadJS library includes (this list is not exhaustive)

  • reload – initiates the loading procedure and defines the array from which you pull URLs for loading
  • loadAll – which iterates through the array and loads the assets one after the other
  • loadFile – to load a single file
  • BrowserDetect -  to determine the current browser, version, operating system, and other environmental variables
  • installPlugin – to register a plug in
  • setPaused – to pause or resume the current load

There’s a couple of nice demos, such as the preload queue which shows a progress bar that you can check out as well. Download PreLoadJS and find this and other helpful libraries at the CreateJS site. Don’t forget when you publish a Windows 8 app in Canada you can get rewards with Developer Movement, and if you are a student you could enter it in Imagine Cup!