htmlspecialchars()

htmlspecialchars() — Convert special characters to HTML entities.

htmlspecialchars() — Certain characters have special significance in HTML, and should be represented by HTML entities if they are to preserve their meanings. This function returns a string with these conversions made. If you require all input substrings that have associated named entities to be translated, use htmlentities instead.

If the input string passed to this function and the final document share the same character set, this function is sufficient to prepare input for inclusion in most contexts of an HTML document. If, however, the input can represent characters that are not coded in the final document character set and you wish to retain those characters (as numeric or named entities), both this function and htmlentities (which only encodes substrings that have named entity equivalents) may be insufficient. You may have to use mb_encode_numericentity instead.

Inputs: string: The string being converted. encoding: For the purposes of this function, the encodings ISO-8859-1, ISO-8859-15, UTF-8, cp866, cp1251, cp1252, and KOI8-R are effectively equivalent, provided the string itself is valid for the encoding, as the characters affected by htmlspecialchars occupy the same positions in all of these encodings. double_encode: When double_encode is turned off PHP will not encode existing html entities, the default is to convert everything.

Returns: The converted string. If the input string contains an invalid code unit sequence within the given encoding an empty string will be returned, unless either the ENT_IGNORE or ENT_SUBSTITUTE flags are set.