FireFox invalid regex group

Question

I have the following regex that works fine in chrome but it does not work in FireFox generating syntax error Invalid Regex Group :

bld = txt.split(/(?<=:)/iu,1);

I have tried to escape : using /(?<=\\:)/iu but it gives the same error. I could not able to figure out the cause of this problem.

Answer 1

As you can see here , as of now, lookbehinds are not supported in every browser/JavaScript environment. Thus, you can't actually rely on that feature if you want to support all browsers including legacy versions.

Since you just want to match 0+ chars other than : and the first : in the string, you may use

s.match(/^[^:]*:/)

See the regex demo .

JS:

 console.log( 'Error 5: the lorem lipsum: in...'.match(/^[^:]*:/)[0] );