If you add the Browser Object you can run javascript to return the current time on the device (computer/phone/tablet)
Browser.ExecJS("const CurDate = new Date(); CurDate.getHours();")
the above will return the current hour - from 0 to 23.
if you want to prevent people from changing the time on their device to cheat, then you have to request the current time from a time server using AJAX, but if someone wants to cheat, they can get around that too.