JavaScript: Test if hour inside time span

Using JavaScript, how can I test if an hour is inside a time span?

I cannot just use less than or greater than tests because the hour "0" comes immediately after the hour "23".

If a session begins at 23 (11:00 pm) and lasts for 3 hours, 1 (1:00 am) is inside the session but 9 (9:00 am) is outside the session.

  function checkSessionStatus (SessionStartTime, SessionLength, TimeCurrent) {
   if(1==1) return "Session is active"
   else return "Session is NOT active"
  }

  alert(checkSessionStatus(1, 12, 3));  // Session is active
  alert(checkSessionStatus(22, 12, 3));  // Session is active
  alert(checkSessionStatus(0, 2, 3));  // Session is NOT active
  alert(checkSessionStatus(22, 2, 3));  // Session is NOT active

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LVL 16
hankknightAsked:
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EikromanConnect With a Mentor Commented:
Hello,

I'm assuming that the session can last 24 hours max (every hour will then be active)
I'm assuming that start time and current time is in range of [0-23]
The start hour and end hour counts in.

The logic:
If the TimeCurrent is less than SessionStartTime and the sessions spans over two different days (StartTime+Length is greater or equal to 24), then we move the SessionStartTime 24 hours back and recursively call the function.

Then we simply verify if TimeCurrent is greater or equal to SessionStartTime AND is less or equal to end time (SessionStartTime+SessionLength).

The code:
 function checkSessionStatus (SessionStartTime, SessionLength, TimeCurrent) {
 DAY_LENGTH=24;
  	
  	if(SessionStartTime+SessionLength>=DAY_LENGTH&&SessionStartTime>TimeCurrent)
  		return checkSessionStatus(SessionStartTime-DAY_LENGTH, SessionLength, TimeCurrent);
  	else
  		{
  			if(TimeCurrent>=SessionStartTime && TimeCurrent <= SessionStartTime+SessionLength)
  				return "Session is active";
  			else
  				return "Session is NOT active";
  		}
   
  }

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Let me know if you need further clarification or have any other question regarding this.
0
 
Sar1973Connect With a Mentor Commented:
You should record the start and end date with a script like:
var myStartDate = (StartDate);
var myEndDate = (EndDate);
function CheckSession(myEndDate ) {
	var myDate = new Date(); 
	var myDiv1 = document.getElementById("hideshow1");
	var myDiv2 = document.getElementById("hideshow2");
	if (myDate >myStartDate && myDate<myEndDate) {
		alert("In session");
	} else {
		alert("Out of session");
	}
}

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