PHP字符串函数htmlentities()的用法

htmlentities

(PHP 4, PHP 5)

htmlentities — Convert all applicable characters to HTML entities

说明

string htmlentities
( string $string
[, int $flags = ENT_COMPAT | ENT_HTML401
[, string $encoding = ini_get("default_charset")
[, bool $double_encode = true
]]] )

This function is identical to htmlspecialchars() in all ways, except with htmlentities(), all characters which have HTML character entity equivalents are translated into these entities.

If you want to decode instead (the reverse) you can use html_entity_decode().

参数

string

The input string.

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_COMPAT | 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 &#FFFD; (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 &#FFFD; (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.

An optional argument defining the encoding used when converting characters.

If omitted, the default value of the encoding varies depending on the PHP version in use. In PHP 5.6 and later, the default_charset configuration option is used as the default value. PHP 5.4 and 5.5 will use UTF-8 as the default. Earlier versions of PHP use ISO-8859-1.

Although this argument is technically optional, you are highly encouraged to specify the correct value for your code if you are using PHP 5.5 or earlier, or if your default_charset configuration option may be set incorrectly for the given input.

支持以下字符集： 支持的字符集列表 字符集 别名 描述 ISO-8859-1 ISO8859-1 西欧，Latin-1 ISO-8859-5 ISO8859-5 Little used cyrillic charset (Latin/Cyrillic). ISO-8859-15 ISO8859-15 西欧，Latin-9。增加欧元符号，法语和芬兰语字母在 Latin-1(ISO-8859-1) 中缺失。 UTF-8   ASCII 兼容的多字节 8 位 Unicode。 cp866 ibm866, 866 DOS 特有的西里尔编码。本字符集在 4.3.2 版本中得到支持。 cp1251 Windows-1251, win-1251, 1251 Windows 特有的西里尔编码。本字符集在 4.3.2 版本中得到支持。 cp1252 Windows-1252, 1252 Windows 特有的西欧编码。 KOI8-R koi8-ru, koi8r 俄语。本字符集在 4.3.2 版本中得到支持。 BIG5 950 繁体中文，主要用于中国台湾省。 GB2312 936 简体中文，中国国家标准字符集。 BIG5-HKSCS   繁体中文，附带香港扩展的 Big5 字符集。 Shift_JIS SJIS, 932 日语 EUC-JP EUCJP 日语 MacRoman   Mac OS 使用的字符串。 ''   An empty string activates detection from script encoding (Zend multibyte), default_charset and current locale (see nl_langinfo() and setlocale()), in this order. Not recommended.

Note: 其他字符集没有认可。将会使用默认编码并抛出异常。

When double_encode is turned off PHP will not encode existing html entities. The default is to convert everything.

返回值

Returns the encoded 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.

更新日志

版本 说明 5.6.0 The default value for the encoding parameter was changed to be the value of the default_charset configuration option. 5.4.0 The default value for the encoding parameter was changed to UTF-8. 5.4.0 The constants ENT_SUBSTITUTE, ENT_DISALLOWED, ENT_HTML401, ENT_XML1, ENT_XHTML and ENT_HTML5 were added. 5.3.0 The constant ENT_IGNORE was added. 5.2.3 The double_encode parameter was added.

范例

Example #1 A htmlentities() example

<?php
$str = "A 'quote' is <b>bold</b>";

// Outputs: A 'quote' is &lt;b&gt;bold&lt;/b&gt;
echo htmlentities($str);

// Outputs: A &#039;quote&#039; is &lt;b&gt;bold&lt;/b&gt;
echo htmlentities($str, ENT_QUOTES);
?>

Example #2 Usage of ENT_IGNORE

<?php
$str = "x8F!!!";

// Outputs an empty string
echo htmlentities($str, ENT_QUOTES, "UTF-8");

// Outputs "!!!"
echo htmlentities($str, ENT_QUOTES | ENT_IGNORE, "UTF-8");
?>

参见

html_entity_decode() - Convert all HTML entities to their applicable characters get_html_translation_table() - 返回使用 htmlspecialchars 和 htmlentities 后的转换表 htmlspecialchars() - Convert special characters to HTML entities nl2br() - 在字符串所有新行之前插入 HTML 换行标记 urlencode() - 编码 URL 字符串