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Summary of four security filtering functions in PHP (with code)

不言Original: 2018-08-03 13:59:464059browse

This article introduces to you a summary of the four security filtering functions in PHP (with code). It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.

1. Stripslashes() function

The main function of stripslashes() is to delete backslashes

<?php
echo stripslashes("Who\&#39;s Bill Gates?");
?>

Output result:

Who&#39;s Bill Gates?

2. htmlentities() function

htmlentities() converts characters into HTML entities

<?php
$str = "<? W3S?h????>";
echo htmlentities($str);
?>

The HTML output of the above code is as follows (view source code):

<!DOCTYPE html>
<html>
<body>
<© W3Sçh°°¦§>
</body>
</html>

Browser output of the above code:

<? W3S?h????>

3, htmlspecialchars() function

Convert the predefined characters "448aca1b32fd4c68ec1ee71fe5da5ba6" (greater than) converted to HTML entity:

<?php
$str = "This is some <b>bold</b> text.";
echo htmlspecialchars($str);
?>

The HTML output of the above code is as follows (view source code):

<!DOCTYPE html>
<html>
<body>
This is some <b>bold</b> text.
</body>
</html>

The browser output of the above code:

This is some <b>bold</b> text.

4. strip_tags() function

Strips the HTML tags in the string:

strip_tags() function strips the HTML, XML and PHP in the string Label.

Comments: This function always strips HTML comments. This cannot be changed via the allow parameter.

Note: This function is binary safe.

<?php
echo strip_tags("Hello <b>world!</b>");
?>

Hello world!

Summary of four security filtering functions in PHP (with code)

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