function getXMLHTTP() { //fuction to return the xml http object
		var xmlhttp=false;	
try{
		xmlhttp=new XMLHttpRequest();
		
if (xmlhttp.overrideMimeType) {
xmlhttp.overrideMimeType('text/xml; charset=utf-8');
}
		
}
		catch(e)	{		
			try{			
				xmlhttp= new ActiveXObject("Microsoft.XMLHTTP");
if (xmlhttp.overrideMimeType) {
xmlhttp.overrideMimeType('text/xml; charset=utf-8');
}

			}
			catch(e){
				try{
				xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
if (xmlhttp.overrideMimeType) {
xmlhttp.overrideMimeType('text/xml; charset=utf-8');
}
				}
				catch(e1){
					xmlhttp=false;
				}
			}
		}
		 	
		return xmlhttp;
    }
	
	function grafigiguncelle(tcmbkur,tcmbkursuresi) {
		var tcmbkur = document.getElementById("tcmbkur");
    var tcmbkursuresi = document.getElementById("tcmbkursuresi");
	var tcmbdurum = document.getElementById("tcmbdurum");
	
	var gunsayisi = tcmbkursuresi.options[tcmbkursuresi.selectedIndex].value;
    var kurismi = tcmbkur.options[tcmbkur.selectedIndex].value;
	var tcmbdurumu = tcmbdurum.options[tcmbdurum.selectedIndex].value;
	var strURL="tcmbkurgrafigi.php?tcmbkur="+kurismi+"&tcmbdurum="+tcmbdurumu+"&limiti="+gunsayisi;
		var req = getXMLHTTP();
		if (req) {
			
			req.onreadystatechange = function() {
				if (req.readyState == 4) {
					// only if "OK"
					if (req.status == 200) {						
						document.getElementById('tcmbkurgrafigi').innerHTML=req.responseText;
					} else {
						alert("There was a problem while using XMLHTTP:\n" + req.statusText);
					}
				}				
			}			
			req.open("GET", strURL, true);
			req.send(null);
		}			
				
	}