Regular Expressions 101

^start of line

Group 1((https?):\/\/)?

?repeats the group contents below at most once:

Group 2(https?)

httpthe literal text http (case sensitive)

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

:the literal : (58₁₀ / 72₈ / 3A₁₆)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

Group 3([wW]{3}\.)?

?repeats the group contents below at most once:

Character Class[wW]{3}

{3}matches exactly 3 characters from the set below:

wthe literal w (119₁₀ / 167₈ / 77₁₆) (case sensitive)

Wthe literal W (87₁₀ / 127₈ / 57₁₆) (case sensitive)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Character Class[a-zA-Z0-9\-.]{3,}

{3,}matches at least 3 characters from the set below:

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

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

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

\-the literal - (45₁₀ / 55₈ / 2D₁₆)

.the literal . (46₁₀ / 56₈ / 2E₁₆)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Character Class[a-zA-Z]{2,}

{2,}matches at least 2 characters from the set below:

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

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

Group 4(\.[a-zA-Z]{2,})?

?repeats the group contents below at most once:

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Character Class[a-zA-Z]{2,}

{2,}matches at least 2 characters from the set below:

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

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

$end of line

Global pattern flags

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

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

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

^((https?):\/\/)?([wW]{3}\.)?[a-zA-Z0-9\-.]{3,}\.[a-zA-Z]{2,}(\.[a-zA-Z]{2,})?$

New

This is currently working for:

http://www.google.com
www.google.com
but not for

google.com
http://google.com