Uploading fillable forms to adobe sign

Couple of issues/questions when loading fillable PDFs to Adobe Sign:

1. Is it true that the javascript is stripped away when the fillable PDF is uploaded to Adobe Sign. What else do I loose

2. Does the fillable PDF have to be designed in a certain way so it can be uploaded and processed by Adobe sign?  It seems Adobe Sign is having issues with drop-down boxes

Thanks in advance for all the help