var durationXmlHttp;

//Get durations
function showDurations(str, start, curr)
{ 
	if(start==0)
	{
		enterBlankDurations();
		return;
	}

	durationXmlHttp=GetDurationXmlHttpObject();
	if (durationXmlHttp==null)
 	{
 		alert ("Browser does not support HTTP Request");
 		return;
 	}
	if (str==null)
 	{
 		str=getCourseInnerValue();
 	}
	var url="getDurations.php";
	url=url+"?span_course="+str+"&curr_span="+curr+"&span_start="+start+"&sid="+Math.random();
	document.getElementById("durationdiv").innerHTML=" <img src='loader.gif' alt=''/> Checking available durations...";
	durationXmlHttp.onreadystatechange=durationChanged;
	durationXmlHttp.open("GET",url,true);
	durationXmlHttp.send(null);
}

function durationChanged() 
{ 
	if (durationXmlHttp.readyState==4 || durationXmlHttp.readyState=="complete")
 	{ 
 		document.getElementById("durationdiv").innerHTML=durationXmlHttp.responseText;
 	} 
}


function enterBlankDurations()
{
	var newHTML="<select disabled class='durationdisabled' name='duration' id='duration' onchange=''>";
	newHTML=newHTML+"<option class='choose'>No duration selected</option></select>";
	document.getElementById("durationdiv").innerHTML=newHTML;
}


function getCourseInnerValue()
{
	var foundvalue;
	var foundDiv;
	foundDiv = document.getElementById("coursediv");	

	if(!foundDiv)
	{
		return;
	}

	foundvalue = foundDiv.getElementsByTagName("select");

	if(!foundvalue)
	{
		return;
	}

	return foundvalue[0].value;
}



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

function changeDurationClass(isSelected)
{
	var classString="duration";
		

	if(!isSelected)
	{
		classString="durationEmpty";
	}
	

	document.getElementById("duration").className = classString;
}