Registers:   r1    r2    r3    r4    r5    r6    r7    r8
Status: (status messages go here)
Regular expression	Match
Type here:	entire string	Expression used:
JavaScript code: (one way)
Test string data	Match	Group matches
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Above is a regular expression tester that can be quite useful when developing a regular expression as cookies are used to save the typed input values to use as a starting point the next time the page is loaded. The instructions are as follows.

• Type test expressions to be tested in the text boxes under "Test expressions". Examples: [abc], [bd].
• Type regular expressions to be tested in the text boxes under "Regular Expression to check". Examples: a, b, c, d.
• To test the "Test expressions" against a "Regular expression to check", select the "Check" button to the right to the desired regular expression.
• For each "Test expression", the cell under "Match" will indicate "Yes" an exact match was made, "No" a match was not made, or "Prefix", the "Regular expression to check" matches a prefix of the "Test expression".
• For each "Test expression", the cell under "Result" will indicate the returned match string.

Note that if the "Regular expression to check" has a syntax error (e.g., mismatched parentheses), then a JavaScript error box may appear when trying to check that regular expression. In that case, just find and fix the "Regular expression to check" and try again.

For more information on regular expressions, see Regular expressions: Introduction .

Historical note: This regular expression checker was originally created in February 2002 using just HTML and JavaScript. It was updated in July 2019 using HTML, JavaScript, and PHP.