How can the "iconv()" function in PHP be used to handle illegal characters during character encoding conversion?

When using the "iconv()" function in PHP to convert character encodings, illegal characters may cause the function to fail. To handle these illegal characters, you can use the "//IGNORE" flag in the "iconv()" function, which will ignore any illegal characters during the conversion process.

// Input string with potential illegal characters
$inputString = "Hello, this is a tést string with illegal characters";

// Convert the input string from UTF-8 to ASCII, ignoring any illegal characters
$outputString = iconv('UTF-8', 'ASCII//IGNORE', $inputString);

// Output the converted string
echo $outputString;