问题
I'm trying to debug with Firefox 59.0.2. I'm inside a function and most of my watch expressions are "(unavailable)". They have values that sometimes display in the scope tab and will display if I use alert() to echo them to the screen.
What is causing this problem? Is there a scope issue? I think the global scope variables aren't having this issue.
I am not getting any javascript errors in console.
回答1:
This is often because you're pausing the debugger at a different point in the call stack than where the variable is in scope. Here's a potential clue.
来源：https://stackoverflow.com/questions/50125252/why-are-my-watch-expressions-unavailable-in-firefox-debugger