var checkflag = "false";
var graphs_up = "true";

/* Hide and display the graphs */
function show_hide(field) {
    element = document.getElementById(field)
    element.style.visibility = 'visible';
    
    if (graphs_up == "false") {
        graphs_up = "true";
        new Effect.SlideDown(element);
    }
    else {
        graphs_up = "false";
        new Effect.SlideUp(element); 
        window.setTimeout('Effect.Appear(\'demo-effect-slideup\', {duration:.3})',2500);
    }
}

/* Check or uncheck all the checkboxes*/
function check(field) {
	if (checkflag == "false") {
		for (i = 0; i < field.length; i++){
			field[i].checked = true;
		}
		checkflag = "true";
		return "Uncheck All"; 
	}
	else {
		for (i = 0; i < field.length; i++) {
			field[i].checked = false; 
		}
		checkflag = "false";
		return "Check All"; 
	}
}

/*
 * Check marks all the check boxes in a form
 * @param object chk HTML node reference to the checkbox that got clicked
 * @return void
 */
function checkAll(chk){
    var form = chk.form;
    for (var i=0, end=form.elements.length; i<end; i++){
        if (isCheckbox(form.elements[i])) {
            form.elements[i].checked = chk.checked;
        }
    }
}

/*
 * Tests an HTML node reference to see if it is a check box
 * @param object el HTML node reference to test
 * @return boolean True if it is a checkbox, false otherwise
 */
function isCheckbox(el) {
    return (el.nodeName === 'INPUT' && el.type === 'checkbox');
}

/* Invert the current state of the checkboxes */
function invert(field) {
	for (i = 0; i < field.length; i++) {
		field[i].checked = !(field[i].checked);
	}
	return "Invert All";
}

function please_wait(element) {
    $(element).innerHTML = '<span class="wait"><img src="/images/loading.gif"/>Please Wait...</span>'
}

function please_wait_small(element) {
    document.getElementById(element).style.background = "transparent url(/images/spinner.gif) no-repeat 0px 0px;"
}

function reset_background(element, image) {
    document.getElementById(element).style.background = "transparent url(/images/" + image + ") no-repeat 0px 0px;"
}