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

Substitution

Processing...

Code Generator

Language

Generated Code

const regex = /(?i)^(?!((<\/|<)(h[1-6]|ul|li|script|blockquote)(\s.+)*>))(.+)(?!(<(\/\3)>))$/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('(?i)^(?!((<\\\/|<)(h[1-6]|ul|li|script|blockquote)(\\s.+)*>))(.+)(?!(<(\\\/\\3)>))$', 'gm') const str = `<h2>Lorem ipsum dolor sit amet, consectetur adipiscing elit</h2> Vivamus vel tempor turpis, <strong>non rutrum quam</strong>. Suspendisse ac rhoncus felis, eget porta lectus. Nam vulputate sapien risus, vel vehicula mi volutpat sed. <ul> <li>Sed feugiat nibh at nisl eleifend scelerisque.</li> <li>Aliquam non maximus ipsum. Aliquam erat volutpat.</li> </ul> <h3>Praesent eget diam sit amet leo vehicula sagittis at quis tortor</h3> Nunc nec sem ac nunc tincidunt aliquam ut nec dolor. Nulla facilisi. <img alt="xxxx" src="xxx.png" class="xxxxx"/> <caption><i>ccccc</i></caption> <img alt="xxxx" src="xxx.png" class="xxxxx"/> <i>ccccc</i> <strong>Nunc nec sem ac nunc tincidunt aliquam ut nec dolor. Nulla facilisi.</strong> Vivamus vel tempor turpis, <strong>non rutrum quam</strong>. Suspendisse ac rhoncus felis, eget porta lectus. Nunc nec Nunc nec Nunc nec <blockquote class="twitter-tweet" data-lang="en"><p lang="en" dir="ltr">Vivamus vel tempor turpis <a href=""></a></p>&mdash; xxxxx (@xxxxxx) <a href="https://twitter.com/xxxx/status/x?ref_src=x">February 15, 2019</a></blockquote> <script async src="" charset="utf-8"></script>`; const subst = `<p>$5</p>`; // The substituted value will be contained in the result variable const result = str.replace(regex, subst); console.log('Substitution result: ', result);

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