Regular Expressions 101

^start of line

Negative Lookahead(?!mailto)

mailtothe literal text mailto (case insensitive)

Non-Capturing Group(?:https?|ftp)

1st Alternativehttps?

httpthe literal text http (case insensitive)

s?optionally matches the literal s (115₁₀ / 163₈ / 73₁₆) (case insensitive)

2nd Alternativeftp

ftpthe literal text ftp (case insensitive)

:the literal : (58₁₀ / 72₈ / 3A₁₆)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

Non-Capturing Group(?:\/?(?:[.#@?=]?[a-z0-9\u00a1-\uffff]+)+)+

+repeats the group contents below at least once:

\/?optionally matches the literal / (47₁₀ / 57₈ / 2F₁₆)

Non-Capturing Group(?:[.#@?=]?[a-z0-9\u00a1-\uffff]+)+

+repeats the group contents below at least once:

Character Class[.#@?=]?

?matches at most one character from the set below:

.the literal . (46₁₀ / 56₈ / 2E₁₆)

#the literal # (35₁₀ / 43₈ / 23₁₆)

@the literal @ (64₁₀ / 100₈ / 40₁₆)

?the literal ? (63₁₀ / 77₈ / 3F₁₆)

=the literal = (61₁₀ / 75₈ / 3D₁₆)

Character Class[a-z0-9\u00a1-\uffff]+

+matches at least one character from the set below:

a-zone character from a (97₁₀) to z (122₁₀) (case insensitive)

0-9one character from 0 (48₁₀) to 9 (57₁₀)

\u00a1-\uffffone character from ¡ (161₁₀) to (65535₁₀)

Character Class[.]?

?matches at most one character from the set below:

.the literal . (46₁₀ / 56₈ / 2E₁₆)

Non-Capturing Group(?:png|jpe?g|gif)

1st Alternativepng

pngthe literal text png (case insensitive)

2nd Alternativejpe?g

jpthe literal text jp (case insensitive)

e?optionally matches the literal e (101₁₀ / 145₈ / 65₁₆) (case insensitive)

gthe literal g (103₁₀ / 147₈ / 67₁₆) (case insensitive)

3rd Alternativegif

gifthe literal text gif (case insensitive)

$end of line

Global pattern flags

i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

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

No unit tests · Add a test to get started

Search reference

Regular Expression

^(?!mailto)(?:https?|ftp):\/(?:\/?(?:[.#@?=]?[a-z0-9\u00a1-\uffff]+)+)+[.]?(?:png|jpe?g|gif)$

Unit Tests

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