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Removing HTML comments using PHP, but avoiding the conditions

I am currently using PHP and regex to exclude all HTML comments from the page. The script works well ... too well. It removes all comments, including my conditional comments in. Here is what I have:

<?php
  function callback($buffer)
  {
        return preg_replace('/<!--(.|\s)*?-->/', '', $buffer);
  }

  ob_start("callback");
?>
... HTML source goes here ...
<?php ob_end_flush(); ?>

Since my regex is not too hot, I'm having trouble trying to figure out how to change the pattern to exclude conditional comments, such as:

<!--[if !IE]><!-->
<link rel="stylesheet" href="/css/screen.css" type="text/css" media="screen" />
<!-- <![endif]-->

<!--[if IE 7]>
<link rel="stylesheet" href="/css/ie7.css" type="text/css" media="screen" />
<![endif]-->

<!--[if IE 6]>
<link rel="stylesheet" href="/css/ie6.css" type="text/css" media="screen" />
<![endif]-->

Greetings

+5
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5 answers

HTML, . , - , .

. , . , . , , , .

<!--(?!\s*(?:\[if [^\]]+]|<!|>))(?:(?!-->).)*-->

:

<!--                #01: "<!--"
(?!                 #02: look-ahead: a position not followed by:
  \s*               #03:   any number of space
  (?:               #04:   non-capturing group, any of:
    \[if [^\]]+]    #05:     "[if ...]"
    |<!             #06:     or "<!"
    |>              #07:     or ">"
  )                 #08:   end non-capturing group
)                   #09: end look-ahead
(?:                 #10: non-capturing group:
  (?!-->)           #11:   a position not followed by "-->"
  .                 #12:   eat the following char, it part of the comment
)*                  #13: end non-capturing group, repeat
-->                 #14: "-->"

№ 02 № 11 . # 02 , . # 11 , , # 12 # 13 .

"" "" .

( ), :

<!(--)?(?=\[)(?:(?!<!\[endif\]\1>).)*<!\[endif\]\1>

:

<!                  #01: "<!"
(--)?               #02: two dashes, optional
(?=\[)              #03: a position followed by "["
(?:                 #04: non-capturing group:
  (?!               #05:   a position not followed by
    <!\[endif\]\1>  #06:     "<![endif]>" or "<![endif]-->" (depends on #02)
  )                 #07:   end of look-ahead
  .                 #08:   eat the following char, it part of the comment
)*                  #09: end of non-capturing group, repeat
<!\[endif\]\1>      #10: "<![endif]>" or "<![endif]-->" (depends on #02)

"" "" .

# 02 - : MSDN - .

, . \s* .

+20

, preg_replace_callback. .

<?php
function callback($buffer) {
    return preg_replace_callback('/<!--.*-->/U', 'comment_replace_func', $buffer);
}

function comment_replace_func($m) {
    if (preg_match( '/^\<\!--\[if \!/i', $m[0])) {
        return $m[0];   
    }              

    return '';
}   

ob_start("callback");
?>

... HTML source goes here ...

<?php ob_end_flush(); ?>
+1

, :

<?php
  function callback($buffer) {
    return preg_replace('/<!--[^\[](.|\s)*?-->/', '', $buffer);
  }
  ob_start("callback");
?>
... HTML source goes here ...
<?php ob_end_flush(); ?>

, :

<!--[if !IE]><!-->
<link rel="stylesheet" href="/css/screen.css" type="text/css" media="screen" />
<!-- <![endif]-->

.

- , , , .

Tomalak , , , , , - , ?

+1

- :

/<!--[^\[](.|\s)*?-->/

, , , , .

0

, PHP regex engine : :

'/<!--(.|\s)*(\[if .*\]){0}(.|\s)*?-->/'
0
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