The results show no real difference between iOS 5 and 7 on iPad 2 and between iOS 6 and 7 on 3rd generation iPad. Neither is there much difference between those two devices. iPhone performance has clearly improved in newer devices. The same is true for iPad Mini. Nothing surprising in that, though.

What is notable is that jQuery Mobile does affect the start-up time of the application quite significantly. In most devices, it takes around 0.5s for the deviceready event to trigger. And over 0.4s even on the latest iPhone, not to mention the over a second on 3GS.

Take Aways

So what can we learn from the results? I’d say that if you target older versions of iOS which run on 3GS (or, perhaps iPad 1), you should think long and hard before you adopt a large library like jQuery Mobile. If you still device to go with jQuery Mobile (or similar libraries), the load speed of the app could (and should) be improved by loading the libraries after deviceready . Also, I used the complete library, and you should definitely build your custom version with only the needed components.

Another alternative is to use more lightweight frameworks such as Zepto + Topcoat. The fastest approach, performance wise, is writing JavaScript and CSS without libraries. If you are not comfortable with that, now might be a good time to learn.

All in all, just keep in mind that half a second can feel like a long time and can have an effect on your app ratings and business performance. On the other hand, if you do a lot of other processing on startup, the JavaScript loading times might not be a significant factor in app startup.

Conclusion

As with most questions in software development, my suggestion whether or not to use libraries in Cordova apps is “it depends”. It is a balance between app load performance and developer productivity. Just keep in mind that the libraries you use can have a big impact on load times. Personally, while I do have an app in the app store (published by my previous company) that uses jQuery Mobile, I would not use it in a new project.

What do you think? Do you use libraries in your Cordova apps?

Update: If you read this far, you might also want to check out the post about whether you should minify your resources in a Cordova/PhoneGap app.