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

/
/
im

Test String

Code Generator

Language

Generated Code

const regex = /<a (.*?)test(.*?)<\/a>/im; // Alternative syntax using RegExp constructor // const regex = new RegExp('<a (.*?)test(.*?)<\\\/a>', 'im') const str = `<a style="text-decoration: none;" target="_blank" href="http://example.com/?qs=df8fc6df1b3b6e7b87c5c8da8e2c0ad34b73a19751c15d1b3efbf37c3ded58b9cca09ee6d80e64bc"><img width="120" height="81" border="0" style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 14px; color: #004990;" title="example.com" alt="example.com" src="http://example.com/lib/fe8f12717d67017f72/m/5/20140513_example_Logo1.jpg" /></a></td> </tr> <tr> <td valign="top" align="left"> <table width="100%" cellspacing="0" cellpadding="0" border="0"> <tbody> <tr> <td valign="top" height="17" align="left" style="font-size: 0%;"><img width="1" height="17" border="0" style="display: block;" title="" alt="" src="http://example.com/lib/fe8f12717d62057f7d/m/1/img_spacer.gif" /></td> </tr> <tr> <td valign="top" align="left" style="font-family: Arial,Helvetica,sans-serif; font-size: 11px; color: #656c73; line-height: 18px;">You are subscribed as <a reportname="mailto:_EMAIL__" style="text-decoration: none; color: #505050;" href="example@example.com"><span class="link3" style="text-decoration: none;">example@example.com</span></a></td> </tr> <tr> <td valign="top" height="25" align="left" style="font-size: 0%;"><img width="1" height="25" border="0" style="display: block;" title="" alt="" src="http://example.com" /></td> </tr> <tr> <td valign="top" align="left" style="font-family: Arial,Helvetica,sans-serif; font-size: 11px; color: #656c73; line-height: 18px;">View and manage your <span class="applefooterlinks">example.com </span><a style="text-decoration: underline; color: #656c73;" target="_blank" href="http://example.com/"><span class="link3" style="color: #656c73; text-decoration: underline;">newsletter preferences</span></a>.<br /> If you wish to unsubscribe you must uncheck the box next to the relevant title.</td> </tr> <tr> <td valign="top" height="25" align="left" style="font-size: 0%;"><img width="1" height="25" border="0" style="display: block;" title="" alt="" src="http://example.com" /></td> </tr> <tr> <td valign="top" align="left" style="font-family: Arial,Helvetica,sans-serif; font-size: 11px; color: #656c73; line-height: 18px;"><a style="text-decoration: underline; color: #656c73;" target="_blank" href="http://example.com/?qs=85ea4dcfb406c17e184090f0720216d008d21d0363ca86741a296ce98649846e5262048f59eea25e"><span class="link3" style="color: #656c73; text-decoration: underline;">TEST</span></a>`; // Reset `lastIndex` if this regex is defined globally // regex.lastIndex = 0; let m; if ((m = regex.exec(str)) !== null) { // 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