Regular Expressions 101

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/
(?:<([a-z]+).*?>)|(?:<\/([a-z]+)\s*?>)
/
gi
1st Alternative
(?:<([a-z]+).*?>)
Non-capturing group
(?:<([a-z]+).*?>)
< matches the character < with index 6010 (3C16 or 748) literally (case insensitive)
1st Capturing Group
([a-z]+)
Match a single character present in the list below
[a-z]
+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
a-z matches a single character in the range between a (index 97) and z (index 122) (case insensitive)
.
matches any character (except for line terminators)
*? matches the previous token between zero and unlimited times, as few times as possible, expanding as needed (lazy)
> matches the character > with index 6210 (3E16 or 768) literally (case insensitive)
2nd Alternative
(?:<\/([a-z]+)\s*?>)
Non-capturing group
(?:<\/([a-z]+)\s*?>)
< matches the character < with index 6010 (3C16 or 748) literally (case insensitive)
\/ matches the character / with index 4710 (2F16 or 578) literally (case insensitive)
2nd Capturing Group
([a-z]+)
Match a single character present in the list below
[a-z]
+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
a-z matches a single character in the range between a (index 97) and z (index 122) (case insensitive)
\s
matches any whitespace character (equivalent to [\r\n\t\f\v ])
*? matches the previous token between zero and unlimited times, as few times as possible, expanding as needed (lazy)
> matches the character > with index 6210 (3E16 or 768) literally (case insensitive)
Global pattern flags
g modifier: global. All matches (don't return after first match)
i modifier: insensitive. Case insensitive match (ignores case of [a-zA-Z])
Your regular expression does not match the subject string.Try launching the debugger to find out why.

Regular Expression
No Match

/
/
gi

Test String