JavaScript doesn't work

Question

My whole JS Freezes when there is an error at the middle of the Script. The first line is just a prompt and the middle is a "switch " . However, the prompt works without the switch...

Please reply!

Ps. I have searched but none of the topics are related to mine.

Answer 1

Add : after case "-9" on line 13.
Delete case keyword on line 16.

Answer 2

code link please

Answer 3

https://code.sololearn.com/W3qMBBS3wt5h/?ref=app

Answer 4

is it that one mistake can make the whole script freeze?