Regex string: specific requirement -

i trying regex string right don't seem working should.

i have numeric field should have 5 digits. digits can start 04xxx , 5xxxx

this string not covering completly:

/[05][0-9][0-9][0-9][0-9]/ 

it forces start 0 or 5 followed 4 digits, allows example 012345

any ideas?

try regex pattern:

^(04|5\d)\d{3}$