var xmlHttp

function calcdates(str)
{ 
	xmlHttp=GetXmlHttpObject();
	if (xmlHttp==null)
	  {
	  alert ("Your browser does not support AJAX!");
	  return;
	  } 
	var url="calcdates.asp";
	url=url+"?q="+str;
	url=url+"&sid="+Math.random();
	xmlHttp.onreadystatechange=stateChanged;
	xmlHttp.open("GET",url,true);
	xmlHttp.send(null);
}
	


function stateChanged() 
	{ 
	if (xmlHttp.readyState==4)
	{ 
	document.getElementById('results').innerHTML=xmlHttp.responseText;
	}
	}

function GetXmlHttpObject()
	{
	var xmlHttp=null;
	try
	  {
	  // Firefox, Opera 8.0+, Safari
	  xmlHttp=new XMLHttpRequest();
	  }
	catch (e)
	  {
	  // Internet Explorer
	  try
	    {
	    xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
	    }
	  catch (e)
	    {
	    xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
	    }
	  }
	return xmlHttp;
}


function isDate(dateStr) {

	var datePat = /^(\d{1,2})(\/|-)(\d{1,2})(\/|-)(\d{4})$/;
	var matchArray = dateStr.match(datePat);

	if (matchArray == null) {
		alert("Please enter date as either mm/dd/yyyy or mm-dd-yyyy.");
		return false;
	}

	month = matchArray[1];
	day = matchArray[3];
	year = matchArray[5];

	if (month < 1 || month > 12) {
		alert("Month must be between 1 and 12.");
		return false;
	}

	if (day < 1 || day > 31) {
		alert("Day must be between 1 and 31.");
		return false;
	}

	if ((month==4 || month==6 || month==9 || month==11) && day==31) {
		alert("Month "+month+" doesn't have 31 days!")
		return false;
	}

	if (month == 2) {
		var isleap = (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0));
		if (day > 29 || (day==29 && !isleap)) {
			alert("February " + year + " doesn't have " + day + " days!");
			return false;
		}
	}
	return true;
}