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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\'s Bill Gates?"); ?>
Output result:
Who'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!
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