Using PHP to check if there are unsuitable characters in a textarea form

The $handle is given the value of '1' even if there are no characters in the text area which appear in the array.

$handle = '';
$message 'nothing in here except plain text';


        // check message doesnt contain odd characters
        $check = 'href,http,#,¥,²,æ,é,Hello. And Bye.,£,$,ˆ,ª,³,¦,½,å,œ,…,§,¾,‡,»,ç,º,³,ä,¿,Â,¶,¸,µ,Ž,°,Œ,Å,’,€,â,¢,¬,ƒ,Æ,†,±,š,¡,Ñ,‘,Ë,‹,¹,·,Þ,`';
        
        $check = explode(",", $check);

        $num = count($check);
        
        $num = $num + 1;
        
        $count = 0;

        while ($count < $num) {
            
            if (strpos($message,$check[$count]) !== false) {
            $handle = 1; break;
            }
            
            $count++;
        }

Here is the improved, bug-free version of your code.

Bugs

1. In $message, the = sign is missing between $message and string 'nothing in here except plain text'.

2. $handle is set as an empty string (''), but it’s better to use 0 or boolean false.

3. Adding 1 to $num was unnecessary and could cause an error.

4. The original code was a bit confusing. It can be improved for clarity and better flow.

Improvements:

• Removal of Unnecessary Calculations: Removed $num and $count variables for simplicity.
• Use of foreach Loop: This is more readable than a while loop and eliminates the need for a counter.
• Variable Naming: Improved readability with clear variable names ($checkChars and $checkArray).

<?php
    $handle = 0;
    $message = 'nothing in here except plain text href';
    
    // Check message doesn't contain odd characters
    $checkChars = 'href,http,#,¥,²,æ,é,Hello. And Bye.,£,$,ˆ,ª,³,¦,½,å,œ,…,§,¾,‡,»,ç,º,³,ä,¿,Â,¶,¸,µ,Ž,°,Œ,Å,’,€,â,¢,¬,ƒ,Æ,†,±,š,¡,Ñ,‘,Ë,‹,¹,·,Þ,`';
    $checkArray = explode(",", $checkChars);
    
    foreach ($checkArray as $char) {
        if (strpos($message, $char) !== false) {
            $handle = 1;
            break;
        }
    }
    
    echo $handle;

Online Demo