PHP How to remove HTML and PHP tags from string

php editor Xiaoxin introduces you how to use PHP to remove HTML and PHP tags from strings. In web development, we often need to process text containing tags. In order to obtain plain text content, we can use the strip_tags() function in PHP to remove HTML tags and the preg_replace() function to remove PHP tags. These two functions can be used together to easily remove markers from strings, allowing you to process text content more conveniently. Next, let’s learn more about how to operate it!

Remove HTML and PHP tags from strings

introduction: In data processing, it is often necessary to remove HTML and PHP tags from strings to obtain plain text content or to prevent unnecessary code execution. PHP provides a variety of functions and regular expressions to achieve this goal.

Method 1: strip_tags() function

strip_tags() function removes all HTML and PHP tags from a string, including comments and scripts. Its syntax is as follows:

string strip_tags(string $str, string $allow_tags = null)

Among them, $str is the string to be processed, and $allow_tags is an optional parameter specifying the list of HTML tags to be retained. For example:

$str = "<h1>Hello, world!</h1><p>This is a paragraph.</p>";
$result = strip_tags($str); // Output: "Hello, world!This is a paragraph."

Method 2: Regular expression

Regular expressions provide a more flexible way to remove HTML and PHP tags. The following regular expressions can be used:

/<(!--.*?-->|<?.*??>|(?<=[^>])><[^>] )&gt ;/s

This regular expression will match all HTML and PHP tags, including comments, scripts, and self-closing tags. Through the preg_replace() function, it can be removed:

$str = "<h1>Hello, world!</h1><p>This is a paragraph.</p>";
$result = preg_replace("/<(!--.*?-->|<?.*??>|(?<=[^>])><[^> ] )>/s", "", $str);

Method 3: DOMDocument class

The DOMDocument class provides low-level access to XML and HTML documents. This class allows you to remove HTML tags from a string by:

1. Create a DOMDocument object and load the string.
2. Use the loadHTML() method to load strings.
3. Call the saveHTML() method to save the document as a string containing plain text with the markup removed.

$str = "<h1>Hello, world!</h1><p>This is a paragraph.</p>";
$dom = new DOMDocument();
$dom->loadHTML($str);
$result = $dom->saveHTML();

Performance comparison:

There are subtle differences in performance between these three methods. For smaller strings, the strip_tags() function is usually the fastest. For larger strings, regular expressions may be slightly faster. The DOMDocument class is slow when processing complex HTML documents.

Method of choosing:

Which method to choose depends on the specific needs and the type of string being processed. For simple text processing, the strip_tags() function is usually sufficient. For more complex needs, regular expressions or the DOMDocument class provide more control options.

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