Backend Development
PHP Tutorial
PHP 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 "<" （小于）和 ">" （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 '
< （小于）成为 <
> （大于）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。
<?php $str = "This is some <b>bold</b> text."; echo htmlspecialchars_decode($str); ?>
会被解析成
This is some <b>bold</b> text.
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!
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
1387
52
PHP 8.4 Installation and Upgrade guide for Ubuntu and Debian
Dec 24, 2024 pm 04:42 PM
PHP 8.4 brings several new features, security improvements, and performance improvements with healthy amounts of feature deprecations and removals. This guide explains how to install PHP 8.4 or upgrade to PHP 8.4 on Ubuntu, Debian, or their derivati
How To Set Up Visual Studio Code (VS Code) for PHP Development
Dec 20, 2024 am 11:31 AM
Visual Studio Code, also known as VS Code, is a free source code editor — or integrated development environment (IDE) — available for all major operating systems. With a large collection of extensions for many programming languages, VS Code can be c
Explain JSON Web Tokens (JWT) and their use case in PHP APIs.
Apr 05, 2025 am 12:04 AM
JWT is an open standard based on JSON, used to securely transmit information between parties, mainly for identity authentication and information exchange. 1. JWT consists of three parts: Header, Payload and Signature. 2. The working principle of JWT includes three steps: generating JWT, verifying JWT and parsing Payload. 3. When using JWT for authentication in PHP, JWT can be generated and verified, and user role and permission information can be included in advanced usage. 4. Common errors include signature verification failure, token expiration, and payload oversized. Debugging skills include using debugging tools and logging. 5. Performance optimization and best practices include using appropriate signature algorithms, setting validity periods reasonably,
How do you parse and process HTML/XML in PHP?
Feb 07, 2025 am 11:57 AM
This tutorial demonstrates how to efficiently process XML documents using PHP. XML (eXtensible Markup Language) is a versatile text-based markup language designed for both human readability and machine parsing. It's commonly used for data storage an
PHP Program to Count Vowels in a String
Feb 07, 2025 pm 12:12 PM
A string is a sequence of characters, including letters, numbers, and symbols. This tutorial will learn how to calculate the number of vowels in a given string in PHP using different methods. The vowels in English are a, e, i, o, u, and they can be uppercase or lowercase. What is a vowel? Vowels are alphabetic characters that represent a specific pronunciation. There are five vowels in English, including uppercase and lowercase: a, e, i, o, u Example 1 Input: String = "Tutorialspoint" Output: 6 explain The vowels in the string "Tutorialspoint" are u, o, i, a, o, i. There are 6 yuan in total
Explain late static binding in PHP (static::).
Apr 03, 2025 am 12:04 AM
Static binding (static::) implements late static binding (LSB) in PHP, allowing calling classes to be referenced in static contexts rather than defining classes. 1) The parsing process is performed at runtime, 2) Look up the call class in the inheritance relationship, 3) It may bring performance overhead.
What are PHP magic methods (__construct, __destruct, __call, __get, __set, etc.) and provide use cases?
Apr 03, 2025 am 12:03 AM
What are the magic methods of PHP? PHP's magic methods include: 1.\_\_construct, used to initialize objects; 2.\_\_destruct, used to clean up resources; 3.\_\_call, handle non-existent method calls; 4.\_\_get, implement dynamic attribute access; 5.\_\_set, implement dynamic attribute settings. These methods are automatically called in certain situations, improving code flexibility and efficiency.
The Roles of HTML, CSS, and JavaScript: Core Responsibilities
Apr 08, 2025 pm 07:05 PM
HTML defines the web structure, CSS is responsible for style and layout, and JavaScript gives dynamic interaction. The three perform their duties in web development and jointly build a colorful website.
