PHP strip_tags method to retain multiple HTML tags

This article introduces the method of PHP strip_tags function to retain multiple HTML tags. You can use the second parameter to set tags that do not need to be deleted, mainly involving the second parameter of strip_tags

strip_tags function

Syntax
string strip_tags (string str [, string allowable_tags])
Returns a string with HTML tags removed; you can use the second parameter to set tags that do not need to be deleted.

Usage:

Premise: If there is such a string now,

$str = "<p>我来自<b><a href=&#39;http://www.php.cn&#39;>PHP中文网</a></b></p>";

1, without retaining any HTML tags, the code will be like this:

echo strip_tags($str); 
// 输出：我来自PHP中文网

2. If you want to retain only the 3499910bf9dac5ae3c52d5ede7383485 tag, you only need to write the 3499910bf9dac5ae3c52d5ede7383485 string into the second parameter of strip_tags:

echo strip_tags($str, "<a>"); 
// 输出：我来自<a href=&#39;http://www.php.cn&#39;>PHP中文网</a>

3. To retain e388a4556c0f65e1904146cc1a846bee and < ;b>...Multiple tags, just separate the multiple tags with spaces and write them to the second parameter of strip_tags:

echo strip_tags($str, "<p> <b>"); 
// 输出：<p>我来自<b>PHP中文网</b></p>

What if you want to use php to delete specific tags in the html tag?

This requires code to implement, as follows:

function strip_selected_tags($text, $tags = array()) {
  $args = func_get_args();
  $text = array_shift($args);
  $tags = func_num_args() > 2 ? array_diff($args, array($text)) : (array) $tags;
  foreach($tags as $tag) {
    if (preg_match_all(&#39;/<&#39;.$tag.
        &#39;[^>]*>([^<]*)</&#39;.$tag.
        &#39;>/iu&#39;, $text, $found)) {
      $text = str_replace($found[0], $found[1], $text);
    }
  }
 
  return preg_replace(&#39;/(<(&#39;.join(&#39;|&#39;, $tags).
    &#39;)( | |.)*/>)/iu&#39;, &#39;&#39;, $text);
}
 
$str = "[url="] 123[/url]";
    echo strip_selected_tags($str, array(&#39;b&#39;));

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