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

/
/
g

Test String

Code Generator

Language

Generated Code

const regex = /<[^>]+>/g; // Alternative syntax using RegExp constructor // const regex = new RegExp('<[^>]+>', 'g') const str = ` <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <head> <title>Online regex tester and debugger: JavaScript, Python, PHP, and PCRE</title> <link href="//fonts.googleapis.com/css?family=Open+Sans:400,700,300&amp;subset=latin" rel="stylesheet" type="text/css"> <link href="/css/main.1433274325.css" rel="stylesheet" type="text/css"> <link type="text/plain" rel="author" href="//regex101.com/humans.txt"> <link rel="icon" href="/favicon.ico" type="image/x-icon"> <link href="//maxcdn.bootstrapcdn.com/font-awesome/4.2.0/css/font-awesome.min.css" rel="stylesheet"> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1"> <meta name="keywords" content="javascript,regex,regular expression,debugger,explainer,helper,tester,match,pcre,python,editor"> <meta name="description" content="Online regex tester, debugger with highlighting for PHP, PCRE, Python and JavaScript."> <meta name="author" content="Firas Dib"> <meta property="twitter:card" content="summary"> <meta property="twitter:site" content="@regex101"> <meta property="twitter:title" content="Regex101 - online regex editor and debugger"> <meta property="twitter:description" content="Regex101 allows you to create, debug, test and have your expressions explained for PHP, PCRE, JavaScript and Python. The website also features a community where you can share useful expressions."> <meta property="twitter:creator" content="@regex101"> <meta property="twitter:image" content="//regex101.com/gfx/preview.png"> <meta property="twitter:domain" content="regex101.com"> </head> <body class="box_overflow_fix light default" spellcheck="false"> <div id="header_parent"> <div id="header"> <div id="header_menu"> <a target="_blank" href="https://twitter.com/regex101"><i class="fa fa-twitter-square "></i><span class="large_menu">RegEx101</span></a> <a target="_blank" href="https://www.paypal.com/cgi-bin/webscr?cmd=_donations&amp;business=firas%2edib%40gmail%2ecom&amp;lc=US&amp;item_name=Regex101&amp;no_note=0&amp;currency_code=USD&amp;bn=PP%2dDonationsBF%3abtn_donate_SM%2egif%3aNonHostedGuest"><i class="fa fa-dollar"></i><span class="large_menu">Donate</span></a> <a target="_blank" href="mailto:contact@regex101.com"><i class="fa fa-send"></i><span class="large_menu">Contact</span></a> <a target="_blank" href="https://github.com/firasdib/Regex101/issues"><i class="fa fa-exclamation-triangle"></i><span class="large_menu">Bug reports &amp; Suggestions</span></a> <div id="settings_popup"> <span class="fa-stack fa-lg" id="settings" title="Adjust settings and theme"> <i class="fa fa-circle fa-stack-2x"></i> <i class="fa fa-wrench fa-stack-1x"></i> </span> <span class="fa-stack fa-lg" id="sign_in_out" title="Sign in"> <i class="fa fa-circle fa-stack-2x"></i> <i class="fa fa-sign-in fa-stack-1x"></i> </span> </div> </div> <div class="text_overflow"> <h1 id="logo"> <a href="/"> <div id="large_header"><span class="part1">regular</span> <span class="part2">expressions</span> <span class="part3">101</span></div> <div id="small_header"><span class="part1">reg</span><span class="part2">ex</span> <span class="part3">101</span></div> </a> </h1> <ul id="header_nav"> <li class="fullscreen header_nav active main_menu main" data-id="40"> <i class="fa fa-terminal"></i><span class="large_menu">Regex Tester</span> </li> <li class="fullscreen header_nav main_menu community" data-id="43"> <i class="fa fa-cloud"></i><span class="large_menu">Regex Library</span> </li> <li class="fullscreen header_nav main_menu" data-id="42"> <a target="_blank" href="http://webchat.freenode.net/?nick=regex101-....&amp;channels=regex" id="irc"> <i class="fa fa-comments"></i><span class="large_menu">IRC</span> </a> </li> </ul> </div> </div> </div> <div id="settings_popup_contents"> <div class="left"> <div class="label"><i class="fa fa-gear settings"></i> General Settings</div> <input type="checkbox" id="display_whitespace" name="display_whitespace" tabindex="999" value="1" data-id="1"> <label class="design_label" for="display_whitespace"> <span></span>Display Whitespace </label> <input type="checkbox" id="small_menu" name="small_menu" tabindex="999" value="1" data-id="201"> <label class="design_label" for="small_menu"> <span></span>Use minimal view </label> <div class="label"><i class="fa fa-picture-o theme"></i> Theme</div> <input type="radio" id="light_theme" name="theme" tabindex="999" value="1" data-id="203" checked="checked"> <label class="design_label" for="light_theme"> <span></span>Use light theme </label> <input type="radio" id="dark_theme" name="theme" tabindex="999" value="1" data-id="200"> <label class="design_label" for="dark_theme"> <span></span>Use dark theme </label> </div> <div class="right"> <div id="colorizer_themes"> <div class="label"><i class="fa fa-terminal regex"></i> Regex Settings</div> <input type="checkbox" id="colorize_regex" name="colorize_regex" tabindex="999" value="1" data-id="9"> <label class="design_label" for="colorize_regex"> <span></span>Colorize syntax </label> <div class="select_themes"> <strong>Theme:</strong> <select class="light_themes" data-id="999"> <option value="default">Default</option> <option value="default_light">Default - Light</option> </select><select class="dark_themes" data-id="999"> <option value="default">Default</option> </select> </div> <input type="checkbox" id="smart_completion" name="smart_completion" tabindex="999" value="1" data-id="210"> <label class="design_label" for="smart_completion"> <span></span>Enable smart auto-completion </label> <input type="checkbox" id="wrap_newlines" name="wrap_newlines" tabindex="999" value="1" data-id="10"> <label class="design_label" for="wrap_newlines"> <span></span>Wrap long lines </label> <input type="checkbox" id="highlight_interaction" name="highlight_interaction" tabindex="999" value="0" data-id="220"> <label class="design_label" for="highlight_interaction"> <span></span>Highlight groups </label> <input type="checkbox" id="display_nonpart" name="display_nonpart" tabindex="999" value="0" data-id="221"> <label class="design_label" for="display_nonpart"> <span></span>Show non-participating groups </label> <div class="execution_limit"> <label class="design_label" for="execution_limit">Max execution time:</label> <input type="text" name="execution_limit" id="execution_limit" placeholder="2000"><em>ms</em> </div> </div> <!--li id="dark_theme" data-id="200" class="menu_item"> <i class="fa fa-picture-o"></i><span class="large_menu">Use dark theme</span> </li--> </div> <div class="arrow-box-tip reverse"></div> </div> <div class="denial_of_service" id="splash"> <div> Initializing editor, please stand by... <i class="fa fa-cog fa-spin"></i> </div> </div> <div class="denial_of_service" id="loading_screen"> <div> Loading content, please hold... <i class="fa fa-cog fa-spin"></i> </div> </div> <noscript> <div class="denial_of_service"> <div> It seems like you have JavaScript disabled, rendering this website virtually useless. 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extension_window"></div> <div id="regex_editor" class="box_overflow_fix"> <div id="code_samples" class="extension_window box_overflow_fix overflow_handler"></div> <div id="regex_debugger" class="box_overflow_fix extension_window"> <div id="regex_debugger_bg" class="box_overflow_fix"> <div class="label" id="debugger_label">Status: Fetching debug info...</div> <div id="label_container" class="monospace"> <input type="checkbox" id="show_regex_pos" name="show_regex_pos" tabindex="999" value="1" checked="checked"/> <label class="design_label" for="show_regex_pos"> <span></span>Display position in pattern </label> <input type="checkbox" id="internal_opt" name="internal_opt" tabindex="999" value="1"/> <label class="design_label" for="internal_opt"> <span></span>Disable internal engine optimizations </label> <a href="#" id="debugger_collapse">collapse all</a> </div> </div> <div id="regex_debugger_window" class="overflow_handler"> <div class="debugger_loader_padding"></div> </div> </div> <div id="main_editor" class="flex-container box_overflow_fix"> <div id="regex_container" class="flex-regex box_overflow_fix"> <label for="regex"> Regular Expression <div id="version_container" style="display: none;"> &mdash; <select id="version_selector"> </select> </div> <span id="result_indicator" class="no_match">no match</span> </label> <div id="regex_input" class="box_overflow_fix richtext_parent"> <div id="delimiter_selector" class="richtext_left slash_menu slash box_overflow_fix" data-dropdown=".delimiter-dropdown">/</div> <div class="richtext_right"> <div class="slash slash_menu" data-dropdown=".delimiter-dropdown">/</div><!-- --><div id="options_container"> <input data-focus="#options_container" value="" id="options" name="options" size="20" tabindex="2" type="text" placeholder="gmixXsuUAJ"/> <i id="options_helper" class="fa fa-question-circle"></i> </div> <div id="options_helper_contents"></div> </div> <div class="richtext_padding"> <div class="richtext_container" id="richtext_regex_container"> <div class="richtext" id="richtext_regex"> <pre><span class="colorizer_height"></span><br/></pre> <pre id="regex_colors"><span></span><br/></pre> <textarea data-focus="#richtext_regex_container" spellcheck="false" id="regex" name="regex" tabindex="1" rows="1" cols="50" placeholder="insert your regular expression here" autofocus="autofocus"></textarea> </div> </div> </div> </div> </div> <div id="test_result_container" class="box_overflow_fix flex-text "> <label for="regex_string">Test string</label> <div class="overflow_handler flex-grow"> <div class="richtext" id="richtext_test"> <pre><span id="richtext_test_size"></span><br>&nbsp;</pre> <pre id="richtext_test_colors"><span id="test_color_element"></span><br></pre> <textarea wrap="off" data-focus="#test_result_container .overflow_handler" spellcheck="false" id="regex_string" class="box_overflow_fix" name="test" rows="10" tabindex="3" placeholder="insert your test string here"></textarea> </div> </div> </div> <div id="subst_parent" class="box_overflow_fix flex-sub "> <label for="sub" class="expander collapsed"> <span class="fa fa-plus-circle"></span>Substitution </label> <div id="subst_container" class="overflow_handler flex-grow"> <input class="box_overflow_fix" value="" id="sub" name="sub" tabindex="3" type="text" placeholder="substitution; \\num = backreference, \\n = newline, \\t = tab"> <div id="subst_area" class="overflow_handler flex-grow"> <div contenteditable="true" id="subst_result" class="monospace hard_break box_overflow_fix"></div> </div> </div> </div> <div id="unit_tests_builder" class="box_overflow_fix flex-unit-builder"> <div class="label">Create test<div class="right"><a href="#" class="button" tabindex="23">Add test</a></div></div> <div id="unit_test_creator" class="box_overflow_fix"> <div class="test_builder"> <div class="the_test pt1"> <div class="left">given the string</div> <div class="right"><textarea tabindex="19" class="box_overflow_fix" id="unit_data" placeholder="test string"></textarea></div> </div> <div class="the_test pt2"> <div class="left"><span>assert that</span><select id="unit_type" tabindex="20"></select><select tabindex="21" id="assert_type"></select></div> <div class="right"><textarea tabindex="22" class="box_overflow_fix" id="assert_equals" type="text" placeholder="string value"></textarea></div> </div> </div> </div> </div> <div id="unit_tests_list" class="box_overflow_fix flex-unit-list"> <div class="label">Test list<div class="right unit_test_player"><i class="fa fa-play run_tests" title="Run tests (CTRL+K)"></i><span class="unit_result">n/a</span></div></div> <div id="unit_test_window" class="unit_test_window flex-grow overflow_handler"> <div class="all_tests"> <div id="unit_test_container"> </div> </div> </div> </div> </div> <div id="regex_treeview" class="box_overflow_fix"> <div id="treeview_resizer" title="Keep dragging"><div></div></div> <div id="treeview_content" class="box_overflow_fix flex-container"> <div id="scroll_treeview" class="box_overflow_fix flex-elem"> <div id="explainer_label" class="label expander"> <span class="fa"></span>Explanation </div> <div class="overflow_handler box_overflow_fix flex-grow"> <div id="treeview" style="height: 100%"> An explanation of your regex will be automatically generated as you type. </div> </div> </div> <div id="scroll_match" class="box_overflow_fix flex-elem"> <div id="match_label" class="label expander"> <span class="fa"></span>Match information </div> <div class="overflow_handler box_overflow_fix flex-grow"> <div id="match_info"> Detailed match information will be displayed here automatically. </div> </div> </div> <div id="quickref" class="box_overflow_fix flex-elem"> <div class="label expander"> <span class="fa"></span>Quick reference </div> <div id="quickref_data" class="flex-grow"> <div id="first_menu" class="box_overflow_fix general_menu"> <ul> <li class="menu_notice"> <div class="filter_input filter_mini box_overflow_fix" id="quickref_filter_parent"> <i class="fa fa-search"></i> <div class="filter_div"> <input data-focus="#quickref_filter_parent" type="text" id="quickref_filter" class="filter_parent box_overflow_fix" name="quickref_filter" value="" placeholder="filter"> </div> </div> <span class="text_overflow" style="margin-right: 5px;">Full reference</span> </li> <li class="menu_item" data-id="basic"><i class="fa fa-star"></i>Most used tokens</li> <li class="menu_item" data-id="fullref"><i class="fa fa-database"></i>All tokens</li> <li class="menu_notice">Categories</li> <li class="menu_item" data-id="other"><i class="fa fa-dot-circle-o"></i>General tokens</li> <li class="menu_item" data-id="anchors"><i class="fa fa-anchor"></i>Anchors</li> <li class="menu_item" data-id="meta"><i class="fa fa-bolt"></i>Meta sequences</li> <li class="menu_item" data-id="quantifiers"><i class="fa fa-asterisk"></i>Quantifiers</li> <li class="menu_item" data-id="groups"><i class="fa fa-dot-circle-o"></i>Group constructs</li> <li class="menu_item" data-id="charclass"><i class="fa fa-th-large"></i>Character classes</li> <li class="menu_item" data-id="modifiers"><i class="fa fa-flag"></i>Flags/Modifiers</li> <li class="menu_item" data-id="subst"><i class="fa fa-scissors"></i>Substitution</li> <li class="menu_item" id="quickref_search"><i class="fa fa-search"></i>Search result</li> </ul> </div> <div id="second_menu" class="no_icon box_overflow_fix general_menu overflow_handler"> <ul class="no_icon"></ul> </div> </div> </div> </div> </div> </div> </div> <div class="delimiter-dropdown dropdown dropdown-relative dropdown-tip dropdown-index"> <ul class="dropdown-menu"> <li><a href="#">/</a></li> <li><a href="#">~</a></li> <li><a href="#">@</a></li> <li><a href="#">;</a></li> <li><a href="#">&#37;</a></li> <li><a href="#">\`</a></li> </ul> </div> <div id="dimmer"></div> <div id="dimmer-popup"></div> <div id="match-tooltip" class="arrow-box monospace"> <div id="tooltip-contents"></div> <div id="match-tooltip-tip" class="arrow-box-tip"></div> </div> <script src="/js/underscore-min.1433274318.js" type="text/javascript"></script> <script src="//ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js" type="text/javascript"></script> <script src="/js/jquery.tools.1433274318.js" type="text/javascript"></script> <script src="/js/general.regex101.1433274319.js" type="text/javascript"></script> <script src="/js/colorParser.regex101.1433274323.js" type="text/javascript"></script> <script src="/js/explainer.regex101.1433274320.js" type="text/javascript"></script> <script>(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)})(window,document,'script','//www.google-analytics.com/analytics.js','ga');ga('create','UA-33878479-1','regex101.com');ga('send','pageview');</script> <script src="/js/common.regex101.1433274322.js" type="text/javascript"></script> <script src="/js/matcher.regex101.1433274321.js" type="text/javascript"></script> </body> </html>`; // 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