var _request = null;
var _ctrlId  = null;

function getConcentrations(catValue, concntrnId)
{
    _ctrlId = concntrnId;
    _request = createXMLHttpRequestObject();
    getRecords(catValue)
}

function getRecords(value)
{
    var _URL = "Ajax-Server-Page.aspx?CatId="+escape(parseInt(value));
    _request.open("GET", _URL, true);
    _request.onreadystatechange = getServerResponse;
    _request.send(null);
}

function getServerResponse()
{
    if(_request.readyState == 4)
    {
        if(_request.status == 200)
        {
	        populateRelevantList();			
        }
    }
}

function populateRelevantList()
{
    document.getElementById(_ctrlId).length = 0;
    document.getElementById(_ctrlId).disabled = true;
    if(_request.responseText != "")
    {
        var _response = _request.responseText.split(':');
        for(var x=0; x<_response.length; x++)
        {
            var tempOptions = _response[x].split(',');
            var newOption = new Option(tempOptions[1],tempOptions[0]);
            document.getElementById(_ctrlId).options[x] = newOption;
        }
    }
    else
    {
        var newOption = new Option("All","0");
        document.getElementById(_ctrlId).options[0] = newOption;
    }
    document.getElementById(_ctrlId).disabled = false;
}