How can debugging techniques be used to identify the root cause of a string replacement function not working as intended in PHP, particularly when dealing with form data inputs?

The issue with the string replacement function not working as intended in PHP when dealing with form data inputs could be due to incorrect variable handling or improper use of the str_replace function. To identify the root cause, you can use debugging techniques such as printing out the input data, checking the variable values, and verifying the function parameters.

// Example code snippet to fix string replacement function issue with form data inputs
$input_data = $_POST['input_data']; // Assuming input_data is the form field name
$old_string = 'old_value';
$new_string = 'new_value';

if(isset($input_data)){
    $replaced_data = str_replace($old_string, $new_string, $input_data);
    echo "Replaced data: " . $replaced_data;
} else {
    echo "No input data received";
}