This function tries to return a string with all HTML and PHP tags stripped from a given str. It uses the same tag stripping state machine as the fgetss() function.
You can use the optional second parameter to specify tags which should not be stripped.
Note: allowable_tags was added in PHP 3.0.13 and PHP 4.0b3.
Since PHP 4.3.0, HTML comments are also stripped. This is hardcoded and can not be changed with allowable_tags.
Because strip_tags() does not actually validate the HTML, partial, or broken tags can result in the removal of more text/data than expected.
This function does not modify any attributes on the tags that you allow using allowable_tags, including the style and onmouseover attributes that a mischievous user may abuse when posting text that will be shown to other users.
strip_tags() has been binary safe since PHP 5.0.0
See also htmlspecialchars().