PHP strip_tags Function | Remove HTML Tags from String

PHP strip_tags is an inbuilt function in PHP. It removes all HTML, PHP tags and NULL bytes from a string after processing. It returns the same string after removing HTML and PHP tags. In this article, we will discuss the PHP strip_tags Function. Also, we will discuss a few examples of using it.

Note: You should not use this function to prevent XSS attacks. However, you can use htmlspecialchars or any other function depending on the context.

Syntax

string strip_tags( $string, $allowable_tags )

Parameters

The PHP strip_tags function expects two parameters. However, one parameter is mandatory and the other is optional.

  • $string: The input string is the first parameter. Also, it is a mandatory parameter.
  • $allowable_tags: The second parameter specifies a list of tags to not remove from the string. Also, it is an optional parameter.

Note: The function will always strip HTML Comments and PHP tags as they are hardcoded. Also, you cannot change this behavior by allowable_tags parameter.

Return Value

The PHP strip_tags function returns a string after removing HTML and PHP tags along with the Null bytes from the string.

Note: The function does not validate the HTML. Therefore, partial or invalid tags may result in the removal of more data than expected.

PHP strip_tags Function

Examples

Let’s discuss a few examples of using the function.

Example 1: Removing All Tags

For instance, consider the example for removing all the tags from the input string.

<?php
	$htmlString = '<p>Test paragraph.</p><!-- Comment --> <a href="#partA">Part A</a>';

	$strippedString = strip_tags($htmlString);
	echo $strippedString;

?>

In the above example, the function removes the paragraph (p), anchor (a) and HTML comments from the string. The output is as follows:

OUTPUT:
Test paragraph. Part A

Example 2: Allowing Some Tags

Alternatively, you can allow some tags using the second parameter. The function will not remove these tags from the string.

<?php
	$htmlString = '<p>Test paragraph.</p><!-- Comment --> <a href="#partA">Part A</a>';

	$strippedString = strip_tags($htmlString, '<a><p>');
	echo $strippedString;

?>

In the above example, we allow the paragraph (p) and anchor (a) tag by passing them in the second parameter. The strip_tags function in PHP strips all the remaining tags from the list.

OUTPUT:
<p>Test paragraph.</p> <a href="#partA">Part A</a>

Conclusion

In conclusion, we discussed the PHP strip_tags Function in this article. You can read more about it on the PHP Official Documentation. Additionally, you can learn more about PHP String Functions on Concatly.

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