Regular Expressions 101

Non-Capturing Group(?:\<[hH]3(?:\s.*?)?\>)

\<the literal < (60₁₀ / 74₈ / 3C₁₆)

Character Class[hH]

hthe literal h (104₁₀ / 150₈ / 68₁₆) (case sensitive)

Hthe literal H (72₁₀ / 110₈ / 48₁₆) (case sensitive)

3the literal 3 (51₁₀ / 63₈ / 33₁₆)

Non-Capturing Group(?:\s.*?)?

?repeats the group contents below at most once:

\sany whitespace character

.*?any character (except for line terminators), repeated any number of times

\>the literal > (62₁₀ / 76₈ / 3E₁₆)

Group 1((.|\s)*?)

Group 2(.|\s)*?

*?repeats the group contents below any number of times:

1st Alternative.

.any character (except for line terminators)

2nd Alternative\s

\sany whitespace character

Positive Lookahead(?=\<\/[hH]3\>)

\<the literal < (60₁₀ / 74₈ / 3C₁₆)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

Character Class[hH]

hthe literal h (104₁₀ / 150₈ / 68₁₆) (case sensitive)

Hthe literal H (72₁₀ / 110₈ / 48₁₆) (case sensitive)

3the literal 3 (51₁₀ / 63₈ / 33₁₆)

\>the literal > (62₁₀ / 76₈ / 3E₁₆)

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

(?:\<[hH]3(?:\s.*?)?\>)((.|\s)*?)(?=\<\/[hH]3\>)

New

<p>  asdf <strong> ghkjk 
   <strong> qwer </p>
<h3 class="lol"> asdf **<strong>** gh
   kjk **<strong>** qwer </h3>

test test test

<h3> tes ttest
</h3>

Regular Expression

Substitution