The filter function in php verifies and filters user input data.

Introduction to PHP Filter

PHP filters are used to verify and filter data from unsafe sources (such as user input.
Copy codeThe Code is as follows:
// Remove html tags or encode special characters
Var_dump (filter_var ("
// Url_encoded encoding, excluding or encoding special characters
Var_dump (filter_var ("http: // Chinese", FILTER_SANITIZE_ENCODED ));

// Html Escape Character "" <> & characters with ASCII values smaller than 32.
Var_dump (filter_var ("<A & B # \"> ", FILTER_SANITIZE_SPECIAL_CHARS ));

// Delete All characters except letters, numbers, and! # $ % & '* +-/=? ^ _ '{| }~ @. []
Var_dump (filter_var ("AS $ &> <", FILTER_SANITIZE_EMAIL ));

// Delete All characters except letters, numbers, and $-_. +! * '(), {}|\\^ ~ [] '<> # % ";/? : @ & =
Var_dump (filter_var ("k <>! ", FILTER_SANITIZE_URL ));

// Delete All characters except numbers and +-
Var_dump (filter_var ("123ABC ++", FILTER_SANITIZE_NUMBER_INT ));

// Delete All characters except numbers, +-, and. and eE.
Var_dump (filter_var ("mm., pp", FILTER_SANITIZE_NUMBER_FLOAT ));

// Apply addslashes
Var_dump (filter_var ("aa //'' ", FILTER_SANITIZE_MAGIC_QUOTES ));

// Verify the value in an integer in the specified range
Var_dump (filter_var (20, FILTER_VALIDATE_INT, array ("options" => array ("min_range" => 10, "max_range" => 51 ))));

// If it is "1", "true", "on", and "yes", true is returned. If it is "0", "false", "off ", "no" and "", false is returned. Otherwise, NULL is returned.
Var_dump (filter_var (1, FILTER_VALIDATE_BOOLEAN ));

// Verify the value with a floating point number.
Var_dump (filter_var (222, FILTER_VALIDATE_FLOAT ));

// Verify the URL
Var_dump (filter_var ("http://www.baidu.com", FILTER_VALIDATE_URL ));

// Verify email
Var_dump (filter_var ("abcd@123.com", FILTER_VALIDATE_EMAIL ));

// Verify the IP address
Var_dump (filter_var ("1.1.1.266", FILTER_VALIDATE_IP ));