Regex to check a substring is having all numeric or not (in Java script).

Question

Hi, I am using following code to check first four characters are alphabate or not.

var pattern = new RegExp('^[A-Z]{4}');
if (enteredID.match(pattern))
    isValidAlphabates = true;
else {
    isValidAlphabates = false;

This is working fine; Now I need to check the next 6 characters (of the entered text) need to be only numeric (0 to 9).

I ve the option to use substring or substr method to extract that part & use the regular experssion: ^[0-9]{6}.

But is there a better way to do it, without using the substring method here.

Answer 1

To clarify, the ^ means "at the start of the string". So you can combine your two regexes to say "start with four A-Z then have six 6 0-9."

var pattern = new RegExp('^[A-Z]{4}[0-9]{6}');

Answer 2

var pattern = new RegExp('^[A-Z]{4}[0-9]{6}');

Answer 3

var pattern = new RegExp('^[A-Z]{4}[0-9]{6}$');

I added $ that means that checked string must end there.

Answer 4

You can check the whole string at once

var pattern = new RegExp('^[A-Z]{4}[0-9]{6}');