Drew Crawford provides in-depth analysis on the challenges with using Javascript in non-trivial mobile apps:
If we are going to make any progress on the mobile web, or on native apps, or really on anything at all–we need to have conversations that at least appear to have a plausible basis in facts of some kind–benchmarks, journals, quotes from compiler authors, whatever. There have been enough HN comments about “I wrote a web app one time and it was fine”. There has been enough bikeshedding about whether Facebook was right or wrong to choose HTML5 or native apps knowing what they would have known then what they could have known now.
The task that remains for us is to quantify specifically how both the mobile web and the native ecosystem can get better, and then, you know, do something about it. You know–what software developers do.