Using a regular expression to validate an zip code [on hold]

THERE IS A ZIP CODE CHECK,AND THE ZIPCODE IS FROM A INPUT TAG,LIKE THIS

input type="text" id = "zipCode"

YOU MUST INPUT NUMBER BUT ALSO DELIMIT BY COMMA

SO, HOW TO DO THIS IN REGULAR EXPRESSION

---

THE CHECK
1: THE ZIPCODE MUST BE NUMBER
2: EACH ZIPCODE IS INPUTTED BY 3 OR 7 DIGITS, ALTHOUGH IT CAN BE SEPARATED BY COMMAS

---

FOR EXAMPLE:
123
123,
,123
1234567
,1234567
1234567,
123,1234567
1234567,1234567
1234567,123
1234567,123,1234567
1234567,1234567,1234567,1234567
1234567,,1234567,1234567,1234567,.....(.... is the zipcode and you can input much )

THIS FOLLOW CHECKED RESULT IS RIGHT

---

123,1234 OR 1234,123
each zipcode is not 3 or 7 then wrong

aaaaaa,123
each zipcode is not all numbers then wrong

---

I do it in java also scala (the is also same)

x.split(",", 0).foreach(zc =>
              if (!zc.matches("\\d*") || (zc.length != 3 && zc.length != 7)) judge = false)

BUT HOW TO DO IT IN REGULAR EXPRESSION
the three or seven number I can check, But I don't know how to check Each zipCode