regex code assistance for entering 600 in a input field

[Member_15683654]

Hello I was trying to understand how to work with a regex expression for when a User enters starts typing in 600 in the input field, then populate the error message. What would be the regex code for that?
Currently I have `^[\w'\-,.][^0-9_!¡?÷?¿\/\\+=@#$%ˆ&*(){}|~<>;:[\]]{2,}$`

[Lost User]

Do you really need all that just to capture "600"?

[Member_15683654]

thank you for your reply:

Main thing is if customer enters a credit card like 1111222233334444 that is ok, but if customer enters a credit card number that starts with 600 and then other characters then it should be validated. ex: 6001222233334444

[Lost User]

In that case it would be easier just to check if the first 3 characters are "600"; and you can do that with a simple string method in most languages.

[Member_15683654]

How would I do that? I tried with

^600

but it instead it didnt show that error but got rid of it. I want to show the error when customer enters 600 first and any numbers after.

[Richard Deeming]

Looks like you're specifying the pattern for valid values, rather than invalid values. Try:

^([^6]|6[^0]|60[^0])

Regexper[^] regex101: build, test, and debug regex[^]

---

"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

[Lost User]

Why do you need a regex for such a simple test?

if (text.substring(0, 3).equals("600")) // is all you need
...