function IsValidTime(timeStr,timeobj) {
// Checks if time is in HH:MM AM/PM format.

var timePat = /^(\d{1,2})(:(\d{2}))?\s?(AM|am|PM|pm)$/;

var matchArray = timeStr.match(timePat);
var timefield = timeobj;


if (matchArray == null) {
	alert("Time is not in a valid format. H:MM AM|am|PM|pm");
	timefield.value="";
	timefield.focus();
	return false;
}

hour = matchArray[1];
minute = matchArray[3];


if (hour < 0  || hour > 12) {
	alert("Hour must be between 1 and 12.");
	timefield.value="";
	timefield.focus();
	return false;
}

if (minute<0 || minute > 59) {
	alert ("Minute must be between 0 and 59.");
	timefield.value="";
	timefield.focus();
	return false;
}
return true;
}