Takes one parameter, a Source value
Returns the number of bytes in the given Source value, as an integer.
This is a similar command to Len$, which returns the byte count as a string.
Note: Moxie.Build is configured for all pages / data to be in UTF-8. The Len$, Right$, and Left$ functions reference byte counts, not character counts. All non-accented Latin characters, as is normal in English, are one byte per character. However, accented characters and non-Latin characters will be multiple bytes per character. Consideration of these limits should always be used when designing code that uses Len$, Right$, and Left$.