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Example code for PHP strstr function to determine whether a string exists_php basics
Example code for PHP strstr function to determine whether a string exists_php basics
PHP strstr Definition and Usage
The strstr() function searches for the first occurrence of a string in another string.
This function returns the rest of the string (from the matching point). Returns false if the searched string is not found.
Syntax
strstr(string,search)
| Parameters | Description |
|---|---|
| string | Required. Specifies the string to be searched for. |
| search | Required. Specifies the string to search for. If the argument is a number, then searches for characters matching the numeric ASCII value. |
Tips and Notes
Note: This function is binary safe.
Note: This function is case-sensitive. For case-insensitive searches, use stristr().
Example
Example 1
echo strstr("Hello world!","world");
?>
Output:
world!
Example 2
In this example, we will search for the character represented by the ASCII value of "o":
echo strstr("Hello world!",111);
?>
Output:
o world!
PHP uses the strstr() function to prevent spam comments
If your website has a lot of spam comments, most of the spam comments have links. , because you want to increase backlinks, so you can use the following tips to eliminate these spam comments with links.
$content = $_POST['content'];
$garbage = strstr($content, "if($garbage == false)
{
// Database insertion code
}
else
{
echo "<script>alert('Your comment cannot contain links'); history.go(-1);</script>";
}
?>
PHP uses REFERER root access to jump to the address
For example, I developed a Yellow Pages source code and transferred it to the webmaster's home. I have set a demo program address before: But now this domain name needs to be used for other sites, and what should I do if I don’t want the original demo address to become invalid? Then I can use PHP REFERER to determine the source. If it comes from the address of the webmaster's download station, I will transfer it to the site domain name.
I placed the following code in index.php on this site to allow access from files.jb51.net to locate my server's commonly used software download http://s.jb51.net
You can go to the demo address on this page
$referHost = parse_url($_SERVER['HTTP_REFERER'], PHP_URL_HOST);
$validDomain = 'files.jb51.net';
$valid = strstr ($referHost, $validDomain) == $validDomain;
if(!empty($valid)){
echo '<script>location.href="http://s.jb51.net";</script>' ;
exit;
}
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