html_entity

Description

string html_entity_decode ( string string [, int quote_style [, string charset]])

html_entity_decode() is the opposite of htmlentities() in that it converts all HTML entities to their applicable characters from string.

The optional second quote_style parameter lets you define what will be done with 'single' and "double" quotes. It takes on one of three constants with the default being ENT_COMPAT:

表格 1. Available quote_style 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.

The ISO-8859-1 character set is used as default for the optional third charset. This defines the character set used in conversion.

PHP 4.3.0 及其后续版本支持如下字符集。

表格 2. 已支持字符集

字符集	别名	描述
ISO-8859-1	ISO8859-1	西欧，Latin-1
ISO-8859-15	ISO8859-15	西欧，Latin-9。增加了 Latin-1（ISO-8859-1）中缺少的欧元符号、法国及芬兰字母。
UTF-8		ASCII 兼容多字节 8-bit Unicode。
cp866	ibm866, 866	DOS-特有的 Cyrillic 字母字符集。PHP 4.3.2 开始支持该字符集。
cp1251	Windows-1251, win-1251, 1251	Windows-特有的 Cyrillic 字母字符集。PHP 4.3.2 开始支持该字符集。
cp1252	Windows-1252, 1252	Windows 对于西欧特有的字符集。
KOI8-R	koi8-ru, koi8r	俄文。PHP 4.3.2 开始支持该字符集。
BIG5	950	繁体中文，主要用于中国台湾。
GB2312	936	简体中文，国际标准字符集。
BIG5-HKSCS		繁体中文，Big5 的延伸，主要用于香港。
Shift_JIS	SJIS, 932	日文。
EUC-JP	EUCJP	日文。

注: ISO-8859-1 将代替任何其它无法识别的字符集。

例子 1. Decoding HTML entities
<?php $orig = "I'll \"walk\" the dog now"; $a = htmlentities($orig); $b = html_entity_decode($a); echo $a; // I'll "walk" the dog now echo $b; // I'll "walk" the dog now // For users prior to PHP 4.3.0 you may do this: function unhtmlentities($string) { $trans_tbl = get_html_translation_table(HTML_ENTITIES); $trans_tbl = array_flip($trans_tbl); return strtr($string, $trans_tbl); } $c = unhtmlentities($a); echo $c; // I'll "walk" the dog now ?>

注: You might wonder why trim(html_entity_decode(' ')); doesn't reduce the string to an empty string, that's because the ' ' entity is not ASCII code 32 (which is stripped by trim()) but ASCII code 160 (0xa0) in the default ISO 8859-1 characterset.