htmlspecialchars

Convert special characters to HTML entities

&reftitle.description; `string` `htmlspecialchars` `string` `string` `int` `flags` ENT_QUOTES | ENT_SUBSTITUTE | ENT_HTML401 ``string``null```encoding`&null; `bool` `double_encode`&true;

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.

## Performed translations

Character | Replacement
`&` (ampersand) | `&amp;`
`"` (double quote) | `&quot;`, unless `ENT_NOQUOTES` is set
`'` (single quote) | `&#039;` (for `ENT_HTML401`) or `&apos;` (for `ENT_XML1`, `ENT_XHTML` or `ENT_HTML5`), but only when `ENT_QUOTES` is set
`<` (less than) | `&lt;`
`>` (greater than) | `&gt;`

&reftitle.parameters;

`string`

- The `string` being converted.

`flags`

- A bitmask of one or more of the following flags, which specify how to handle quotes, invalid code unit sequences and the used document type. The default is `ENT_QUOTES | ENT_SUBSTITUTE | ENT_HTML401`.

  ## Available `flags` constants

  Constant Name | Description
  `ENT_COMPAT` | Will convert double-quotes and leave single-quotes alone.
  `ENT_QUOTES` | Will convert both double and single quotes.
  `ENT_NOQUOTES` | Will leave both double and single quotes unconverted.
  `ENT_IGNORE` | Silently discard invalid code unit sequences instead of returning an empty string. Using this flag is discouraged as it may have security implications.
  `ENT_SUBSTITUTE` | Replace invalid code unit sequences with a Unicode Replacement Character U+FFFD (UTF-8) or &#xFFFD; (otherwise) instead of returning an empty string.
  `ENT_DISALLOWED` | Replace invalid code points for the given document type with a Unicode Replacement Character U+FFFD (UTF-8) or &#xFFFD; (otherwise) instead of leaving them as is. This may be useful, for instance, to ensure the well-formedness of XML documents with embedded external content.
  `ENT_HTML401` | Handle code as HTML 4.01.
  `ENT_XML1` | Handle code as XML 1.
  `ENT_XHTML` | Handle code as XHTML.
  `ENT_HTML5` | Handle code as HTML 5.

`encoding`

- &strings.parameter.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.

  &reference.strings.charsets;

`double_encode`

- When `double_encode` is turned off PHP will not encode existing html entities, the default is to convert everything.

&reftitle.returnvalues;

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.

&reftitle.changelog;

&Version; | &Description;
8.1.0 | `flags` changed from `ENT_COMPAT` to `ENT_QUOTES` | `ENT_SUBSTITUTE` | `ENT_HTML401`.

&reftitle.examples;

### `htmlspecialchars` example

    <?php
    $new = htmlspecialchars("<a href='test'>Test</a>", ENT_QUOTES);
    echo $new; // &lt;a href=&#039;test&#039;&gt;Test&lt;/a&gt;
    ?>

&reftitle.notes;

Note that this function does not translate anything beyond what is listed above. For full entity translation, see `htmlentities`.

In case of an ambiguous `flags` value, the following rules apply:

- When neither of `ENT_COMPAT`, `ENT_QUOTES`, `ENT_NOQUOTES` is present, the default is `ENT_NOQUOTES`.

- When more than one of `ENT_COMPAT`, `ENT_QUOTES`, `ENT_NOQUOTES` is present, `ENT_QUOTES` takes the highest precedence, followed by `ENT_COMPAT`.

- When neither of `ENT_HTML401`, `ENT_HTML5`, `ENT_XHTML`, `ENT_XML1` is present, the default is `ENT_HTML401`.

- When more than one of `ENT_HTML401`, `ENT_HTML5`, `ENT_XHTML`, `ENT_XML1` is present, `ENT_HTML5` takes the highest precedence, followed by `ENT_XHTML`, `ENT_XML1` and `ENT_HTML401`.

- When more than one of `ENT_DISALLOWED`, `ENT_IGNORE`, `ENT_SUBSTITUTE` are present, `ENT_IGNORE` takes the highest precedence, followed by `ENT_SUBSTITUTE`.

&reftitle.seealso;

- `get_html_translation_table`
- `htmlspecialchars_decode`
- `strip_tags`
- `htmlentities`
- `nl2br`