preg_replace any style tags expression

问题

I am trying to use preg_replace to remove any thing contained in a style tag. For example:

<img src="image.jpg" style="float:left;" />

Would be changed to:

<img src="image.jpg" />

Likewise:

<a href="link.html" style="color:#FF0000;" class="someclass">Link</a>

Would be changed to:

<a href="link.html" class="someclass">Link</a>

How would I write this regular expression?

preg_replace('EXPRESSION', '', $string);

回答1:

This should work:

preg_replace("@(<[^<>]+)\sstyle\=[\"\'][^\"\']+[\"\']([^<>]+>)@i", '$1$2', $string);

回答2:

I recommend using the right tool for the job and avoid using a regular expression.

$dom = new DOMDocument;  
$dom->loadHTML($html); 

$xpath = new DOMXPath($dom);  

foreach ($xpath->query('//*[@style]') as $node) {
    $node->removeAttribute('style'); 
}

echo $dom->saveHTML();

Working Demo

If you must accomplish this job using a regular expression, the following will suffice.

$html = preg_replace('/<[^>]*\Kstyle="[^"]*"\s*/i', '', $html);

Explanation:

<           # '<'
[^>]*       # any character except: '>' (0 or more times)
 \K         #  resets the starting point of the reported match
 style="    #  'style="'
  [^"]*     #    any character except: '"' (0 or more times)
  "         #    '"'
\s*         # whitespace (\n, \r, \t, \f, and " ") (0 or more times)

Working Demo

回答3:

Look for style="..." that is enclosed inside < and > and replace with matched group $1$2

(<.*)style="[^"]*"([^>]*>)

Online Demo

Here is working sample code

Sample code:

<?php
    $re = "/(<.*)style=\"[^\"]*\"([^>]*>)/";
    $str = "<img src=\"image.jpg\" style=\"float:left;\" />\n\n<a href=\"link.html\" style=\"color:#FF0000;\" class=\"someclass\">Link</a>";
    $subst = '$1$2';

    $result = preg_replace($re, $subst, $str);
    print $result;
?>

Output:

<img src="image.jpg"  />

<a href="link.html"  class="someclass">Link</a>

回答4:

This is the best one I could come up with

$re = "/\sstyle\=('|\").*?(?<!\\\\)\1/i";
$str = "<a href=\"link.html\" style=\"color:#FF0000;\"\" class=\"someclass\">Link</a>";
$subst = '';

$result = preg_replace($re, $subst, $str, 1);

outputs

<a href="link.html" class="someclass">Link</a>

demo:

http://regex101.com/r/uW2kB8/8

Explanation:

   \s match any white space character [\r\n\t\f ]
style matches the characters style literally (case insensitive)
\= matches the character = literally
1st Capturing group ('|")
    1st Alternative: '
        ' matches the character ' literally
    2nd Alternative: "
        " matches the character " literally
.*? matches any character (except newline)
    Quantifier: Between zero and unlimited times, as few times as possible, expanding as needed [lazy]
(?<!\\) Negative Lookbehind - Assert that it is impossible to match the regex below
    \\ matches the character \ literally
\1 matches the same text as most recently matched by the 1st capturing group
i modifier: insensitive. Case insensitive match (ignores case of [a-zA-Z])

Which will even handle cases like this.

<a href="link.html" style="background-image:url(\"..\somimage.png\");" class="someclass">Link</a>

and

<a href="link.html" style="background-image:url('..\somimage.png');" class="someclass">Link</a>

and ( which it wont remove )

<a href="link.html" data-style="background-image:url('..\somimage.png');" class="someclass">Link</a>

and even

<a href='link.html' style='color:#FF0000;' class='someclass'>Link</a>

http://regex101.com/r/uW2kB8/11

unlike the other suggestions :)

来源：https://stackoverflow.com/questions/24641744/preg-replace-any-style-tags-expression

标签

php

regex

preg-replace