I have a string of 13 characters say XXXXXXXXXXXXX. I wish to enter a hyphen after every three characters but only for the first three occurrences using JQuery and possibly Regular Expressions.

Which means I need my string to be XXX-XXX-XXX-XXXX.

If I use str.replace(/(.{3})/g, "$1-"), str being my string, as I came across in another post, it yields me XXX-XXX-XXX-XXX-X.

Any help would be greatly appreciated.

Thanks guys.

I have a string of 13 characters say XXXXXXXXXXXXX. I wish to enter a hyphen after every three characters but only for the first three occurrences using JQuery and possibly Regular Expressions.

Which means I need my string to be XXX-XXX-XXX-XXXX.

If I use str.replace(/(.{3})/g, "$1-"), str being my string, as I came across in another post, it yields me XXX-XXX-XXX-XXX-X.

Any help would be greatly appreciated.

Thanks guys.

• javascript
• regex

• Why searching for a hard way? Use loop. – David Jashi Commented Jun 28, 2013 at 7:04
• Thanks for that David but I thought a RegEx will make my life easier :) – Lalit Commented Jun 28, 2013 at 7:05
• 3 What do you have so far? – icedwater Commented Jun 28, 2013 at 7:05
• Hi icedwater, I found a RegEx in another post that is something like str.replace(/(.{3})/, "$1-"). But that will yield a string like XXX-XXX-XXX-XXX-X – Lalit Commented Jun 28, 2013 at 7:08
• @Kumar You should always include that originally, so we know you've attempted something and aren't just telling us to solve it for you – Ian Commented Jun 28, 2013 at 7:09

2 Answers 2

What about .replace(/(.{3})(.{3})(.{3})/,'$1-$2-$3-')?

If you want to do it with Regex this could work...

 // Not nice but works
 var text = "XXXXXXXXXXXXX";
 text.replace(/(...)(...)(...)(....)/g, "$1-$2-$3-$4");
 // Result  "XXX-XXX-XXX-XXXX" Chrome 27+