PHP Filters Advanced
Validate an Integer Within a Range
The following example uses the filter_var() function to check if a variable
is both of type INT, and between 1 and 200:
Example
<?php
$int = 122;
$min = 1;
$max = 200;
if (filter_var($int, FILTER_VALIDATE_INT, array("options" => array("min_range"=>$min, "max_range"=>$max))) === false) {
echo("Variable value is not within the legal range");
} else {
echo("Variable value is within the legal range");
}
?>
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Validate IPv6 Address
The following example uses the filter_var() function to check if the variable $ip is a valid
IPv6 address:
Example
<?php
$ip = "2001:0db8:85a3:08d3:1319:8a2e:0370:7334";
if (!filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6) === false) {
echo("$ip is a valid IPv6 address");
} else {
echo("$ip is not a valid IPv6 address");
}
?>
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Validate URL - Must Contain QueryString
The following example uses the filter_var() function to check if the variable $url is a
URL with a querystring:
Example
<?php
$url = "https://www.w3schools.com";
if (!filter_var($url, FILTER_VALIDATE_URL, FILTER_FLAG_QUERY_REQUIRED) === false) {
echo("$url is a valid URL");
} else {
echo("$url is not a valid URL");
}
?>
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Remove Characters With ASCII Value > 127
The following example uses the filter_var() function to sanitize a string. It
will both remove all HTML tags, and all characters with ASCII value > 127, from
the string:
Example
<?php
$str = "<h1>Hello WorldÆØÅ!</h1>";
$newstr = filter_var($str, FILTER_SANITIZE_STRING, FILTER_FLAG_STRIP_HIGH);
echo $newstr;
?>
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Complete PHP Filter Reference
For a complete reference of all filter functions, go to our complete PHP Filter Reference. Check each filter to see what options and flags are available.
The reference contains a brief description, and examples of use, for each function!
