Regular expression testing App

This app allows you to test regular expressions before using them, ensuring they provide the desired outcomes. Simply enter your regular expression in the input field, specify any modifiers, and input the text you want to test for matches. You can also enter a second regular expression to test simultaneously against the same text. Press the 'Match' button to execute, and the Matching Results section will list any matches found. This dual-testing feature allows for more thorough validation of your regular expressions.

Regular Expression vs. 1.8 Type in your regular expression for testing:
//
//

Modifiers:(g,i,m): //

MultiLine matching

Enter your test string(s) for matching:

Matching or Optimizing result:

Result
Decomposing
Optimizing
Help

JavaScript Regular Expressions Guide

Modifiers

Modifier	Description
i	Perform case-insensitive matching
g	Perform a global match (find all matches rather than stopping after the first match)
m	Perform multiline matching

Brackets

Expression	Description
[abc]	Find any character between the brackets
[^abc]	Find any character NOT between the brackets
[0-9]	Find any digit between the brackets
[^0-9]	Find any non-digit NOT between the brackets
(x\|y)	Find any of the alternatives specified

Groups

Group Type	Description
(...)	Matches the enclosed pattern and captures it (Capturing group).
(?:...)	Matches the enclosed pattern but does not capture it (Non-capturing group).
(?=...)	Lookahead assertion: Matches a group after the main expression without including it in the result.
(?!...)	Negative lookahead assertion: Specifies a group that cannot match after the main expression if the result is to be successful.
(?<name>...)	Matches the enclosed pattern and assigns it to a named group.
(?<=...)	Lookbehind assertion: Matches a group before the main expression without including it in the result.
(?<!...)	Negative lookbehind assertion: Specifies a group that cannot match before the main expression if the result is to be successful.

Quantifiers

Quantifier	Description
n+	Matches any string that contains at least one n
n*	Matches any string that contains zero or more occurrences of n
n?	Matches any string that contains zero or one occurrence of n
n{X}	Matches any string that contains a sequence of X n's
n{X,Y}	Matches any string that contains a sequence of X to Y n's
n{X,}	Matches any string that contains a sequence of at least X n's

Meta characters

Meta character	Description
.	Find a single character, except newline or line terminator
\w	Find a word character
\W	Find a non-word character
\d	Find a digit
\D	Find a non-digit character
\s	Find a whitespace character
\S	Find a non-whitespace character
\b	Find a match at the beginning/end of a word
\B	Find a match not at the beginning/end of a word
\0	Find a NULL character
\n	Find a newline character
\f	Find a form feed character
\r	Find a carriage return character
\t	Find a tab character
\v	Find a vertical tab character
\xxx	Find the character specified by an octal number xxx
\xdd	Find the character specified by a hexadecimal number dd
\uxxxx	Find the Unicode character specified by a hexadecimal number xxxx

Corrections:

30-Sep-2024	Vs 1.8	Improved Optimizer
17-Sep-2024	Vs 1.7	Improved decomposition analysis and added optimization suggestion in a new button and tab called Optimize
25-Aug-2024	Vs 1.6	Added an optional second regular expression line to be tested simultaneously plus updated the help section
17-Aug-2024	Vs 1.5	Added more samples and introduce decomposing of regular expression
19-Nov-2020	Vs 1.4	Added multiline matching
17-Nov-2020	Vs 1.3	Fix a bug in reporting illegal regular expressions
23-Dec-2019	Vs 1.2	Fix a bug in retrieving the history of regular expressions
28-Oct-2019	Vs 1.1	Redesign the GUI Interface
25-Apr-2018	Vs 1	Initial release