Fix strpos PHP Invalid Usage Error

If you encounter any issues while using the strpos() function, you can try the following solutions:

1. Check if the parameters are correct: make sure you are passing the right parameters. The `strpos()` function takes two parameters – the first one is the string to search within, and the second one is the substring to look for. Make sure both of these parameters are passed correctly.
2. Check for return value: The strpos() function returns the index position of the first match, or false if no match is found. If your code relies on the return value of strpos(), make sure you handle it correctly, such as using the === operator to check if it is false.
3. Check character encoding: strpos() function may not work for certain character encodings. Make sure your string and the substring are in the same character encoding. If possible, try using the mb_strpos() function, which supports more character encodings.
4. Check for case sensitivity: The default for the strpos() function is case sensitive. If you want to perform a case-insensitive search, you can use the stripos() function.
5. Check for special characters in a string: Make sure to correctly handle any special characters, such as spaces, punctuation, etc., if they are present in your string or substring. Try using the trim() function to remove any leading or trailing spaces in the string.
6. To perform more complex searches, consider using regular expressions with functions like preg_match().

If none of the above methods have solved the problem, it is recommended to check other parts of the code to see if there are other errors causing the strpos() function to not be used correctly.