Difference Between ExternalCall and ExternalEval

Unity Engine
1

I was wondering Why should I use one and why shoul I use another one

I was guessing that ExternalCall, is newer than ExternalEval, Is that making sense?

I’m asking because till here I could do the same with both, couldn’t I?

Thanks in Advance

2

from the manual: “ExternalCall immediately returns without waiting for the function that was called to complete.”

whereas ExternalEval is a blocking function.

3

I see, I’m sorry I’m a litlle bit newbie on programming.

What does it return, I mean, I should call a function from my html then it would return to my unity code, isn’t it?

What being a blocking function means?

Is there any specif cases that I should use call instead of Eval? Or it is by my needs and what I prefer?