var req;
var xmlresponse;

function loadXMLDoc(url, callBack) {

	req = false;
    // branch for native XMLHttpRequest object
    if(window.XMLHttpRequest) {
    	try {
			req = new XMLHttpRequest();
        } catch(e) {
			req = false;
        }
    // branch for IE/Windows ActiveX version
    } else if(window.ActiveXObject) {
       	try {
        	req = new ActiveXObject("Msxml2.XMLHTTP");
      	} catch(e) {
        	try {
          		req = new ActiveXObject("Microsoft.XMLHTTP");
        	} catch(e) {
          		req = false;
        	}
		}
    }
	if(req) {

		req.onreadystatechange = callBack;
		
		req.open("GET", url, true);

		req.setRequestHeader('Content-Type','text/xml');
		if (navigator.appName == "Microsoft Internet Explorer") {
			req.setRequestHeader ("Pragma", "no-cache");
			req.setRequestHeader ("Cache-Control","no-cache");
	    }
	    
		req.send(null);
	}
}

/*  variant voor post-requests  */
function loadXMLDocPost(url, callBack, params) {

	req = false;
    // branch for native XMLHttpRequest object
    if(window.XMLHttpRequest) {
    	try {
			req = new XMLHttpRequest();
        } catch(e) {
			req = false;
        }
    // branch for IE/Windows ActiveX version
    } else if(window.ActiveXObject) {
       	try {
        	req = new ActiveXObject("Msxml2.XMLHTTP");
      	} catch(e) {
        	try {
          		req = new ActiveXObject("Microsoft.XMLHTTP");
        	} catch(e) {
          		req = false;
        	}
		}
    }
	if(req) {

		req.onreadystatechange = callBack;

		req.open("POST", url, true);

		//req.setRequestHeader('Content-Type','text/xml');
		if (navigator.appName == "Microsoft Internet Explorer") {
			req.setRequestHeader ("Pragma", "no-cache");
			req.setRequestHeader ("Cache-Control","no-cache");
	    }
		/*  extra headers voor post */
		//Send the proper header information along with the request
		req.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
		req.setRequestHeader("Content-length", params.length);
		req.setRequestHeader("Connection", "close");
		req.send(params);
	}
}