Using PHP strip_tags() to Remove HTML Tags

PHP's strip_tags() function removes HTML tags from a string, returning plain text, which helps prevent malicious code injection.

Syntax:

string strip_tags ( string $str [, string $allowable_tags ] )

, where $str is the input string and $allowable_tags optionally specifies tags to keep.

Basic usage: calling strip_tags($str) on a string like " Hello world! " outputs "Hello, world!".

To preserve specific tags, provide them in $allowable_tags, e.g., strip_tags($str, "<b><i>") keeps and tags.

Multiple tags can be listed, such as strip_tags($str, "<b><i><a>"), which retains bold, italic, and anchor tags while stripping others.

Setting $allowable_tags to an empty string removes all tags.

Notes: the function strips all HTML, including script and style tags; attributes can be preserved by including them in $allowable_tags; a wildcard "<>" keeps all tags; for selective removal, preg_replace() with regex may be used.

In summary, strip_tags() provides a simple way to clean user input by stripping unwanted HTML tags while optionally preserving desired ones.