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
Processing...

Test String

Substitution
Processing...

Code Generator

Language

Generated Code

const regex = /"\K[^"]*?feedsportal.*?(?=")/g; // Alternative syntax using RegExp constructor // const regex = new RegExp('"\\K[^"]*?feedsportal.*?(?=")', 'g') const str = `src="http://rss.feedsportal.com/c/669/f/9809/s/3b7b71e8/sc/5/mf.gif" border="0" /><br clear='all'/><br /><br /><a href="http://da.feedsportal.com/r/199108411625/u/49/f/9809/c/669/s/3b7b71e8/sc/5/rc/1/rc.htm" rel="nofollow"><img src="http://da.feedsportal.com/r/199108411625/u/49/f/9809/c/669/s/3b7b71e8/sc/5/rc/1/rc.img" border="0" /></a><br /><a href="http://da.feedsportal.com/r/199108411625/u/49/f/9809/c/669/s/3b7b71e8/sc/5/rc/2/rc.htm" rel="nofollow"><img src="http://da.feedsportal.com/r/199108411625/u/49/f/9809/c/669/s/3b7b71e8/sc/5/rc/2/rc.img" border="0" /></a><br /><a href="http://da.feedsportal.com/r/199108411625/u/49/f/9809/c/669/s/3b7b71e8/sc/5/rc/3/rc.htm" rel="nofollow"><img src="http://da.feedsportal.com/r/199108411625/u/49/f/9809/c/669/s/3b7b71e8/sc/5/rc/3/rc.img" border="0" /></a><br /><br /><a href="http://da.feedsportal.com/r/199108411625/u/49/f/9809/c/669/s/3b7b71e8/sc/5/a2.htm"><img src="http://da.feedsportal.com/r/199108411625/u/49/f/9809/c/669/s/3b7b71e8/sc/5/a2.img" border="0" /></a><img width="1" height="1" src="http://pi.feedsportal.com/r/199108411625/u/49/f/9809/c/669/s/3b7b71e8/sc/5/a2t.img" border="0" />`; const subst = ``; // 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