How to remove %3cbr %3e in php

PHP is a widely used server-side scripting language that makes website development more efficient and easier. However, sometimes when using PHP to develop websites, you will encounter some problems, such as character escaping problems, such as the need to remove
. This article will explain how to use PHP to solve this problem and provide some related tips and suggestions.

What is
?

In web development, character sequences such as are HTML encodings and are used to represent the less-than symbols on the left side of angle brackets and the greater-than symbols on the right side. And "br" is a tag in HTML, used for line breaks. Therefore, when we see
in PHP code, we can understand it as "
", which is the "line break" in HTML.

Why should we remove
?

When using PHP to develop a website, we sometimes need to process some text content, such as content taken out from a database, and then display it on the web page. However, in some cases, the text content will contain HTML tags, such as "

", "
", etc., and we need to remove these tags, leaving only the text content.

For the "
" tag, we usually see
such encoding form in the code. This is because in web pages, the browser parses HTML tags and converts them into corresponding content for display. In PHP code, if these tags are directly removed, it will cause some display problems, such as the lack of line breaks in the text content. Therefore, we need to convert these tags into HTML format first and then process them into plain text content.

How to remove
?

In PHP, you can use some functions and methods to remove
such HTML encoding. Two commonly used methods are introduced below.

Method 1: Use the strip_tags() function

The strip_tags() function is a function used in PHP to remove HTML tags. It can remove all HTML tags in the string, leaving only Download plain text content. Of course, when using the strip_tags() function, you must also pay attention to some details. For example, tags that you do not want to remove can be specified in the function not to be removed. To avoid injection attacks, you need to use htmlentities(), etc.

The following is a code example of using the strip_tags() function to remove
:

<?php
$str = "这是一段包含<br>标签的文本内容。";
$str = str_replace("%3cbr %3e", "<br>", $str); // 将%3cbr %3e替换为<br>
$str = strip_tags($str); // 去除HTML标签
echo $str;
?>

Run the above code, you will get the following output:

这是一段包含标签的文本内容。

Method 2: Use regular expressions Expression

In addition to the strip_tags() function, PHP also supports the use of regular expressions to remove HTML tags. Regular expression is a syntax used to describe and match text patterns. It can identify HTML tags and remove them, leaving only the text content.

The following is a code example of using regular expressions to remove
:

<?php
$str = "这是一段包含<br>标签的文本内容。";
$str = str_replace("%3cbr %3e", "<br>", $str); // 将%3cbr %3e替换为<br>
$str = preg_replace("/<.*?>/si", "", $str); // 去除HTML标签
echo $str;
?>

Run the above code, you will get the following output:

这是一段包含标签的文本内容。

It should be noted that regular expressions The "/s" modifier in the expression means to treat the text as a single string and let "." match any character including newlines.

Summary

This article introduces two methods to remove HTML encoding of
through the strip_tags() function and regular expressions. In actual development, the appropriate method should be selected according to the specific situation and combined with other security measures to ensure the security of the program. In addition, when writing code, you must also ensure readability and maintainability, and avoid errors and BUGs as much as possible.

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