Regular Expressions 101

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/
^(?:http(s)?:\/\/)[\w.-]+(?:\.[\w.-]+)+(?:\/[\w.~:?#[\]@!$&'()*+,;=.-]+)*\/?$
/
gm
^ asserts position at start of a line
Non-capturing group
(?:http(s)?:\/\/)
http
matches the characters http literally (case sensitive)
1st Capturing Group
(s)?
? matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
s matches the character s with index 11510 (7316 or 1638) literally (case sensitive)
: matches the character : with index 5810 (3A16 or 728) literally (case sensitive)
\/ matches the character / with index 4710 (2F16 or 578) literally (case sensitive)
\/ matches the character / with index 4710 (2F16 or 578) literally (case sensitive)
Match a single character present in the list below
[\w.-]
+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
\w matches any word character (equivalent to [a-zA-Z0-9_])
. matches the character . with index 4610 (2E16 or 568) literally (case sensitive)
- matches the character - with index 4510 (2D16 or 558) literally (case sensitive)
This hyphen is treated literally, which might be confusing for others. Consider escaping it or placing at the start or end of the class!
Non-capturing group
(?:\.[\w.-]+)+
+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
\. matches the character . with index 4610 (2E16 or 568) literally (case sensitive)
Match a single character present in the list below
[\w.-]
+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
\w matches any word character (equivalent to [a-zA-Z0-9_])
. matches the character . with index 4610 (2E16 or 568) literally (case sensitive)
- matches the character - with index 4510 (2D16 or 558) literally (case sensitive)
This hyphen is treated literally, which might be confusing for others. Consider escaping it or placing at the start or end of the class!
Non-capturing group
(?:\/[\w.~:?#[\]@!$&'()*+,;=.-]+)*
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
\/ matches the character / with index 4710 (2F16 or 578) literally (case sensitive)
Match a single character present in the list below
[\w.~:?#[\]@!$&'()*+,;=.-]
+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
\w matches any word character (equivalent to [a-zA-Z0-9_])
.~:?#[
matches a single character in the list .~:?#[ (case sensitive)
\] matches the character ] with index 9310 (5D16 or 1358) literally (case sensitive)
@!$&'()*+,;=.
matches a single character in the list @!$&'()*+,;=. (case sensitive)
- matches the character - with index 4510 (2D16 or 558) literally (case sensitive)
This hyphen is treated literally, which might be confusing for others. Consider escaping it or placing at the start or end of the class!
\/
matches the character / with index 4710 (2F16 or 578) literally (case sensitive)
? matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
$ asserts position at the end of a line
Global pattern flags
g modifier: global. All matches (don't return after first match)
m modifier: multi line. Causes ^ and $ to match the begin/end of each line (not only begin/end of string)
Your regular expression does not match the subject string.

Regular Expression
No Match

/
/
gm

Test String

Code Generator

Generated Code

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Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report.
For a full regex reference for JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions