How does PHP handle empty variables and what are the recommended ways to check for empty values?

PHP handles empty variables by considering them as falsy values. To check for empty variables, you can use functions like `empty()`, `isset()`, or check if the variable is equal to an empty string `''`. It's recommended to use `isset()` to check if a variable is set and not null, and use `empty()` to check if a variable is empty or not.

// Check if a variable is set and not null
if(isset($variable)){
    // Variable is set and not null
}

// Check if a variable is empty
if(empty($variable)){
    // Variable is empty
}