Φ cannot be displayed, but φ can. Why?

Questions
1

Some Greek letters here cannot be displayed.

droid_sans_regular.typeface.json is used. Is that particular font not good enough?

It may also be a browser problem. For example, I cannot even write those two letters here properly. I write one “phi” on the left pane here, it will be displayed as another “phi” on the right pane.

2

I’m not sure this forum is the ideal place for such a typeface.js specific question. You probably get more response by posting at stackoverflow.

3

All the glyphs are visible in the json file. Have you checked to see whether these characters are in the file?