function $(id) {
    return document.getElementById(id);
}

function parseValue(xmlDoc, channelId) {
	var returnValue = "-";
	if (xmlDoc != null) {
		var values = xmlDoc.documentElement.getElementsByTagName("actualValue");
		var thisId = 0;

		for (var i = 0; i < values.length; i++) {
			thisId = values[i].getAttribute('channelId');
			if (thisId == channelId) {
				returnValue = values[i].getAttribute('channelValue') + " " + values[i].getAttribute('channelUnit');
			}
		}
	}
	return returnValue;
}


function parseLatestTime(xmlDoc) {

	if (xmlDoc != null) {
		var values = xmlDoc.documentElement.getElementsByTagName("actualValue");

		var timestamp = "2001-01-01 00:00:00";
		var parsetime;

		for (var i = 0; i < values.length; i++) {
			parsetime = values[i].getAttribute('valueTime');
			if (parsetime > timestamp)
				timestamp = parsetime;
		}
		
		return (timestamp);
	}
}


function getStationChannelsValue(stationId, channels, actualValues, timestamp) {
   
    var xmlhttp = null;
    var result = $('ergebnis');

    // Mozilla
    if (window.XMLHttpRequest) {
        xmlhttp = new XMLHttpRequest();
	try {
		netscape.security.PrivilegeManager.enablePrivilege("UniversalBrowserRead");
	} catch (e) {
		//alert("Permissio UniversalBrowserRead denied.");
	}
    }
    // IE
    else if (window.ActiveXObject) {
        xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
    }
    
    var request = "http://www.sommer.at/ActualValues.php";
    request = request + "?function=getStationValuesXml&stationId=" + stationId;
    
    xmlhttp.open("GET", request, true);

    xmlhttp.onreadystatechange = function() {
        if(xmlhttp.readyState != 4) {
        	if (result != null)
            result.innerHTML = '...';
        }
        if(xmlhttp.readyState == 4 && xmlhttp.status == 200) {
        	for (var i = 0; i < channels.length; i++) {
        	  $(actualValues[i]).innerHTML = parseValue(xmlhttp.responseXML, channels[i]);
          }
          $(timestamp).innerHTML = parseLatestTime(xmlhttp.responseXML);
          if (result != null)
          	result.innerHTML = "OK";
        }
    }
    xmlhttp.send(null);
}