Here is a script to calculate and show the phases of the moon. Just enter a date and time (between year 1900 and 2100).
Set Date and Time
Chrome and some other browsers will show a nice date-time picker. If you use an outdated browser please enter date and time like this: 1980-06-06 12:23
Default is current date and time.
If you want to know how this script works, see: Calculating moon phase for a date.