function getTeacher(field,div) {
	selectedOption = field.options.selectedIndex;
	selectedOption = field.options[selectedOption].text;
	var ajax;
	ajax =  new Ajax.Updater(div, conference_url + '?g='+selectedOption, { method:'get' });
	$('gradeValue').value = +selectedOption;
	clearDiv('times');
}

function getTimes(field, div) {
	selectedOption = field.options.selectedIndex;
	selectedOption = field.options[selectedOption].value;	
	var ajax;
	ajax =  new Ajax.Updater(div, conference_url + '?t='+selectedOption, { method:'get' });
}

function getGrade() {
	var searchString = document.location.search;
    searchString = searchString.substring(1);
    var nvPairs = searchString.split("&");
    for (i = 0; i < nvPairs.length; i++) {
         var nvPair = nvPairs[i].split("=");
         var name = nvPair[0];
         var value = nvPair[1];
         if (name == 'gr') {
         	var grade = value;
				if (grade != '') {
					selectedOption = $('grade').selectedIndex = grade;
				}
				break;
         }
    }
	
	getTeacher($('grade'), 'teachers');
}

function clearDiv(div) {
	var ajax;
	ajax =  new Ajax.Updater(div, conference_url + '?cl=1', { method:'get'  });
}

function popup(url) {
	newwindow=window.open(url,'name','height=270,width=450,location=0,toolbar=0,menubar=0');
	if (window.focus) {newwindow.focus()}
	return false;
}