function initialize(){
        updateChart();
}

//Update the chart according to user selection
function updateChart()
{
	displayLoadingImage();

    //
    //we encode the values of all form elements as query parameters
    //
    var elements = document.groupForm.elements;
   	url =document.groupForm.elements.action.value + "?";
    for (var i = 0; i < elements.length; ++i)
    {
        var e = elements[i];        
        url = url + e.name + "=" + escape(e.value);
        if (i<(elements.length-1)){
	             url = url + "&";
        }
    }

    //Now we update the URL of the image to update the chart
   // document.write(url);
    getChart(url);
}