Backend DevelopmentPHP TutorialPHP converts predefined characters into html entity function htmlspecialchars()PHP converts predefined characters into html entity function htmlspecialchars()
实例
把预定义的字符 "" （大于）转换为 HTML 实体：
<?php $str = "This is some <b>bold</b> text."; echo htmlspecialchars($str); ?>
上面代码的 HTML 输出如下（查看源代码）：
<!DOCTYPE html> <html> <body> This is some <b>bold</b> text. </body> </html>
上面代码的浏览器输出如下：
This is some <b>bold</b> text.
定义和用法
htmlspecialchars() 函数把一些预定义的字符转换为 HTML 实体。
预定义的字符是：
& （和号）成为 &
" （双引号）成为 "
' （单引号）成为 '
提示：要把特殊的 HTML 实体转换回字符，请使用 htmlspecialchars_decode() 函数。
语法
htmlspecialchars(string,flags,character-set,double_encode)
| 参数 | 描述 |
| string | 必需。规定要转换的字符串。 |
| flags | 可选。规定如何处理引号、无效的编码以及使用哪种文档类型。 可用的引号类型：
无效的编码：
规定使用的文档类型的附加 flags： ENT_HTML401 - 默认。作为 HTML 4.01 处理代码。 ENT_HTML5 - 作为 HTML 5 处理代码。 ENT_XML1 - 作为 XML 1 处理代码。 ENT_XHTML - 作为 XHTML 处理代码。 |
| character-set | 可选。一个规定了要使用的字符集的字符串。 允许的值：
注释：在 PHP 5.4 之前的版本，无法被识别的字符集将被忽略并由 ISO-8859-1 替代。自 PHP 5.4 起，无法被识别的字符集将被忽略并由 UTF-8 替代。 |
| double_encode | 可选。一个规定了是否编码已存在的 HTML 实体的布尔值。
|
技术细节
| 返回值： | 返回已转换的字符串。 如果 string 包含无效的编码，则返回一个空的字符串，除非设置了 ENT_IGNORE 或者 ENT_SUBSTITUTE 标志。 |
| PHP 版本： | 4+ |
| 更新日志： | 在 PHP 5 中，character-set 参数的默认值改为 UTF-8。 在 PHP 5.4 中，新增了：ENT_SUBSTITUTE、ENT_DISALLOWED、ENT_HTML401、ENT_HTML5、ENT_XML1 和 ENT_XHTML。 在 PHP 5.3 中，新增了 ENT_IGNORE。 在 PHP 5.2.3 中，新增了 double_encode 参数。 在 PHP 4.1 中，新增了 character-set 参数。 |
更多实例
实例 1
把一些预定义的字符转换为 HTML 实体：
<?php $str = "Jane & 'Tarzan'"; echo htmlspecialchars($str, ENT_COMPAT); // 默认，仅编码双引号 echo "<br>";echo htmlspecialchars($str, ENT_QUOTES); // 编码双引号和单引号 echo "<br>";echo htmlspecialchars($str, ENT_NOQUOTES); // 不编码任何引号 ?>
上面代码的 HTML 输出如下（查看源代码）：
<!DOCTYPE html> <html> <body> Jane & 'Tarzan'<br>Jane & 'Tarzan'<br>Jane & 'Tarzan' </body> </html>
上面代码的浏览器输出如下：
Jane & 'Tarzan' Jane & 'Tarzan' Jane & 'Tarzan'
实例 2
把双引号转换为 HTML 实体：
<?php $str = 'I love "PHP".'; echo htmlspecialchars($str, ENT_QUOTES); // 编码双引号和单引号 ?>;
上面代码的 HTML 输出如下（查看源代码）：
<!DOCTYPE html> <html> <body> I love "PHP". </body> </html>
上面代码的浏览器输出如下：
I love "PHP".
htmlspecialchars_decode() 函数把一些预定义的 HTML 实体转换为字符。
会被解析成
<!DOCTYPE html> <html> <body> This is some <b>bold</b> text. </body> </html>
用户商品详情的输出。
<p>
{sh:$info.intro|htmlspecialchars_decode}
</p>The above is the detailed content of PHP converts predefined characters into html entity function htmlspecialchars(). For more information, please follow other related articles on the PHP Chinese website!
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