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    <p>Here's the solution:</p> <pre><code>&lt;?php // here's the pattern: $pattern = '/&lt;(\w+)(\s+(\w+)\s*\=\s*(\'|")(.*?)\\4\s*)*\s*(\/&gt;|&gt;)/'; // a string to parse: $string = 'Hello, try clicking &lt;a href="#paragraph"&gt;here&lt;/a&gt; &lt;br/&gt;and check out.&lt;hr /&gt; &lt;h2&gt;title&lt;/h2&gt; &lt;a name ="paragraph" rel= "I\'m an anchor"&gt;&lt;/a&gt; Fine, &lt;span title=\'highlight the "punch"\'&gt;thanks&lt;span&gt;. &lt;div class = "clear"&gt;&lt;/div&gt; &lt;br&gt;'; // let's get the occurrences: preg_match_all($pattern, $string, $matches, PREG_PATTERN_ORDER); // print the result: print_r($matches[0]); ?&gt; </code></pre> <p>To test it deeply, I entered in the string auto-closing tags like:</p> <ol> <li>&lt;hr /&gt;</li> <li>&lt;br/&gt;</li> <li>&lt;br&gt;</li> </ol> <p>I also entered tags with:</p> <ol> <li>one attribute</li> <li>more than one attribute</li> <li>attributes which value is bound either into <strong>single quotes</strong> or into <strong>double quotes</strong></li> <li>attributes containing single quotes when the delimiter is a double quote and vice versa</li> <li>"unpretty" attributes with a space before the "=" symbol, after it and both before and after it.</li> </ol> <p>Should you find something which does not work in the proof of concept above, I am available in analyzing the code to improve my skills.</p> <p><strong>&lt;EDIT&gt;</strong> I forgot that the question from the user was to avoid the parsing of self-closing tags. In this case the pattern is simpler, turning into this:</p> <pre><code>$pattern = '/&lt;(\w+)(\s+(\w+)\s*\=\s*(\'|")(.*?)\\4\s*)*\s*&gt;/'; </code></pre> <p>The user @ridgerunner noticed that the pattern does not allow <strong>unquoted attributes</strong> or <strong>attributes with no value</strong>. In this case a fine tuning brings us the following pattern:</p> <pre><code>$pattern = '/&lt;(\w+)(\s+(\w+)(\s*\=\s*(\'|"|)(.*?)\\5\s*)?)*\s*&gt;/'; </code></pre> <p><strong>&lt;/EDIT&gt;</strong></p> <h1>Understanding the pattern</h1> <p>If someone is interested in learning more about the pattern, I provide some line:</p> <ol> <li>the first sub-expression (\w+) matches the tag name</li> <li>the second sub-expression contains the pattern of an attribute. It is composed by: <ol> <li>one or more whitespaces \s+</li> <li>the name of the attribute (\w+)</li> <li>zero or more whitespaces \s* (it is possible or not, leaving blanks here)</li> <li>the "=" symbol</li> <li>again, zero or more whitespaces</li> <li>the delimiter of the attribute value, a single or double quote ('|"). In the pattern, the single quote is escaped because it coincides with the PHP string delimiter. This sub-expression is captured with the parentheses so it can be referenced again to parse the closure of the attribute, that's why it is very important.</li> <li>the value of the attribute, matched by <em>almost</em> anything: (.*?); in this specific syntax, using the <strong>greedy match</strong> (the question mark after the asterisk) the RegExp engine enables a "look-ahead"-like operator, which matches anything but what follows this sub-expression</li> <li>here comes the fun: the \4 part is a <strong>backreference operator</strong>, which refers to a sub-expression defined before in the pattern, in this case, I am referring to the fourth sub-expression, which is the first attribute delimiter found</li> <li>zero or more whitespaces \s*</li> <li>the attribute sub-expression ends here, with the specification of zero or more possible occurrences, given by the asterisk.</li> </ol></li> <li>Then, since a tag may end with a whitespace before the "&gt;" symbol, zero or more whitespaces are matched with the \s* subpattern.</li> <li>The tag to match may end with a simple "&gt;" symbol, or a possible XHTML closure, which makes use of the slash before it: (/>|>). The slash is, of course, escaped since it coincides with the regular expression delimiter.</li> </ol> <p>Small tip: to better analyze this code it is necessary looking at the source code generated since I did not provide any HTML special characters escaping.</p>
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    1. PORegEx match open tags except XHTML self-contained tags
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    1. CODoes not match valid tags having attributes with no value, i.e. `<option selected>`. Also does not match valid tags with unquoted attribute values, i.e. `<p id=10>`.
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    2. CO@ridgerunner: Thanks very much for your comment. In that case the pattern must change a bit: $pattern = '/<(\w+)(\s+(\w+)(\s*\=\s*(\'|"|)(.*?)\\5\s*)?)*\s*>/'; I tested it and works in case of non-quoted attributes or attributes with no value.
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    3. COHow about a space before the tag name: `< a href="http://wtf.org" >` I'm pretty sure it is legal, but you don't match it.
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