Regular Expressions 101

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An explanation of your regex will be automatically generated as you type.
Detailed match information will be displayed here automatically.
  • All Tokens
  • Common Tokens
  • General Tokens
  • Anchors
  • Meta Sequences
  • Quantifiers
  • Group Constructs
  • Character Classes
  • Flags/Modifiers
  • Substitution
  • A single character of: a, b or c
    [abc]
  • A character except: a, b or c
    [^abc]
  • A character in the range: a-z
    [a-z]
  • A character not in the range: a-z
    [^a-z]
  • A character in the range: a-z or A-Z
    [a-zA-Z]
  • Any single character
    .
  • Alternate - match either a or b
    a|b
  • Any whitespace character
    \s
  • Any non-whitespace character
    \S
  • Any digit
    \d
  • Any non-digit
    \D
  • Any word character
    \w
  • Any non-word character
    \W
  • Non-capturing group
    (?:...)
  • Capturing group
    (...)
  • Zero or one of a
    a?
  • Zero or more of a
    a*
  • One or more of a
    a+
  • Exactly 3 of a
    a{3}
  • 3 or more of a
    a{3,}
  • Between 3 and 6 of a
    a{3,6}
  • Start of string
    ^
  • End of string
    $
  • A word boundary
    \b
  • Non-word boundary
    \B

Regular Expression
No Match

/
/
gm

Test String

Code Generator

Language

Generated Code

const regex = /mailto:(.*?)">/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('mailto:(.*?)">', 'gm') const str = `<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">\\r\\n<html xmlns="http://www.w3.org/1999/xhtml">\\r\\n<html>\\r\\n<head></head>\\r\\n<body>\\r\\n<a name="top"></a>Back to Category Index</a></p>\\r\\n<p>-----------------------------------<br/></p>\\r\\n\\r\\n67)<a name="e1h1" id="e1h1"></a> Summary: Solar Eclipse 2024 Travel\\r\\n<br/><br/>\\r\\n<p>Name: laure gem wilson\\r\\nRoadtrippers\\r\\n</p>Category: Travel\\r\\n<br/><br/>\\r\\nEmail: <a href="mailto:query-e1h1@email.net">query-e1h1@email.net</a>\\r\\n<br/><br/>\\r\\nOutlet: Roadtrip<br/><br/>\\r\\nDeadline: 7:00 PM EST - 8 July\\r\\n<br/><br/>\\r\\n<p>\\r\\nQuery: \\r\\n<br/><br/>\\r\\nHi, I am on assignment to write a feature about planning a road<br/>trip to experience the Solar Eclipse 2024, including path of<br/>totality, advice about viewing, and recommendations for when and<br/>where to book accommodations, thanks!<br/>\\r\\n</p>\\r\\n<p>\\r\\nRequirements: \\r\\n<br /><br />\\r\\nMust be domestic USA<br/>\\r\\n</p>\\r\\n<p><a href="#top">Back to Top</a> <a href="#Travel">Back to Category Index</a></p>\\r\\n<p>-----------------------------------<br/> `; // Reset `lastIndex` if this regex is defined globally // regex.lastIndex = 0; let m; while ((m = regex.exec(str)) !== null) { // This is necessary to avoid infinite loops with zero-width matches if (m.index === regex.lastIndex) { regex.lastIndex++; } // The result can be accessed through the `m`-variable. m.forEach((match, groupIndex) => { console.log(`Found match, group ${groupIndex}: ${match}`); }); }

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