Hi, I am working to package on HTML5 now. You can package your projects on HTML5 but you have to know some rules to mobile development. Normally, the specifications to mobile development are equals to HTML5 development
But it’s very important that you test all, some functions (for example, ambient occlusion, some C++ functions about UTexture2D) don’t run on HTML5.
Some important links:
How to reduce HTML5 package size
How to build a project on HTML5?
I hope help you!!
Bye