I need to prevent entering 5 digit sequential numbers like 12345, 45678 etc. in a text box.

I had tried with the following regular expression, but it is not working

var regex = /^\(?[0-9]{3}(\-|\)) ?[0-9]{3}-[0-9]{4}$/;

I need to prevent entering 5 digit sequential numbers like 12345, 45678 etc. in a text box.

I had tried with the following regular expression, but it is not working

var regex = /^\(?[0-9]{3}(\-|\)) ?[0-9]{3}-[0-9]{4}$/;

• javascript
• regex

• stackoverflow.com/questions/32852339/… – Nagaraju Commented Jun 14, 2016 at 11:34
• 1 /12345|23456|34567|45678|56789/ and add more as much as you want – YOU Commented Jun 14, 2016 at 11:37
• 1 If you use HTML5 pattern attribute, use (?!(?:01234|12345|23456|34567|45678|56789|67890|78901|89012|90123)$).*. Adjust as needed. – Wiktor Stribiżew Commented Jun 14, 2016 at 11:37
• @WiktorStribiżew's answer allows 123456 (and generally longer strings containing 5-digit sequences), but maybe that's OK – Chris Lear Commented Jun 14, 2016 at 11:43
• 1 @ChrisLear: Yeah, no idea. OP says "5 digit" sequences, maybe 6 digit ones are allowed. If not, ^(?!.*(?:01234|12345|23456|34567|45678|56789|67890|78901|89012|90123)).*$ can be used (with the ^ and $ unnecessary in HTML5 pattern). – Wiktor Stribiżew Commented Jun 14, 2016 at 11:45

2 Answers 2

It is better to use non regular expression based approach for this type of tasks. You can do this easily using indexOf. Regular expressions for these patterns become really complicated and un-readable.

var pattern = '0123456789012345789' //to match circular sequence as well.
if (pattern.indexOf(input) == -1) 
  console.log('good input')
else
  console.log('bad input')

Another approach is used Tilde (~) operator in search functions. Using ~ on -1 converts it to 0. The number 0 is a falsy value, meaning that it will evaluate to false when converted to a Boolean. Anything that is not falsy is truthy.

const input = '12345';
const pattern = '0123456789012345789';
if (~pattern.indexOf(input))
  console.log('pattern in input');
else
  console.log('pattern not in input');

or you can use the includes() method:

const input = '12345';
const pattern = '0123456789012345789';
if (pattern.includes(input))
  console.log('pattern in input');
else
  console.log('pattern not in input');