Why does the regex rule give this result?

Question

Regular Expressions

Why does the rule /\d\d/g match only the first two values ​​100/100, i.e. the value 10 and 10. The

question is why not 100 and 100, because /d is any number from 0 to 9 inclusive.

By idea 1 matches
0 matches
0 matches
Slash does not match
1 matches
0 matches
0 matches

Answer 1

Idea 1 matches

what does it match? with search \цифра\цифра? No, it doesn't match. C \d\dmatches 10.
If you need to compare one character at a time

1 matches
0 matches
0 matches
Slash does not match
1 matches
0 matches
0 matches

then just/\d/g

Answer 2

Your regexp is humanly read like this: "two consecutive digits".
Such an expression cannot coincide with three digits at once, because two, not three, are needed.
If the question is why "23" and "56" do not match in "123/456", it is because 2 and 5 have already been caught (missed) in "12" and "45" and therefore are no longer considered.
If you search for the same regexp in "1234/5678", you will find "12", "34", "56", "78".