$re = '/(<[ul|ol][^>]*?style=\"[^>]*?)(list-style-type:[a-zA-Z0-9:\.\s\(\)\-\,]*;?)([^\"]*\"[^>]*?>)/';
$str = '<ul style="list-style-type:disc">
<li>Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut
<ul style="list-style-type:circle">
<li>Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut</li>
<li>aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit</li>
<li>In voluptate velit esse cillum dolore eu fugiat nulla pariatur.
<ul style="list-style-type:square">
<li>Excepteur sint occaecat cupidatat non proident.</li>
<li>Sunt in culpa qui officia deserunt mollit anim id est laborum.</li>
</ul>
<ul style="list-style-type:square; abc:asd; qwe:10pt">
<ul style="aaa:eeee; list-style-type:square; abc:asd; qwe:10pt" asdas="aeee">
<ul asdsa="eee" style="aaa:eeee; list-style-type:square; abc:asd; qwe:10pt" asdas="aeee">
<ul style="list-style-type:circle;"><li cke:reset="1" cke:indent="1" cke:listsymbol="o" style=""><span></span><span>Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut</span><ul style="list-style-type:square;"><li cke:indent="2" cke:listsymbol="§" style=""><span></span><span>Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut</span></li><li cke:indent="2" cke:listsymbol="§" style=""><span></span><span>aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit</span></li><li cke:indent="2" cke:listsymbol="§" style=""><span></span><span>In voluptate velit esse cillum dolore eu fugiat nulla pariatur. </span><ul style="list-style-type:disc;"><li cke:indent="3" cke:listsymbol="·" style=""><span></span><span>Excepteur sint occaecat cupidatat non proident.</span></li><li cke:indent="3" cke:listsymbol="·" style=""><span></span><span>Sunt in culpa qui officia deserunt mollit anim id est laborum.</span></li></ul></li></ul></li><li cke:indent="1" cke:listsymbol="o" style=""><span></span><span>aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit</span><ul style="list-style-type:square;"><li cke:indent="2" cke:listsymbol="§" style=""><span></span><span>In voluptate velit esse cillum dolore eu fugiat nulla pariatur.
<ol style="list-style-type:lower-roman;"> ';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
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 PHP, please visit: http://php.net/manual/en/ref.pcre.php