function get_element (element_id) {
	if (document.getElementById(element_id)) return document.getElementById(element_id);
	else return null;
}

function ava (does) {
	return;
}

function click_checkbox (imageid, formvar) {
	var formvar_e = get_element(formvar);
	var current_val = formvar_e.value;
	
	var img = get_element(imageid);
	var changeto_val;
	
	if (current_val == 1) changeto_val = 0;
	else if (current_val == 'y') changeto_val = 'n';
	else if (current_val == 0) changeto_val = 1;
	else if (current_val == 'n') changeto_val = 'y';
	else changeto_val = 0;

	if (changeto_val == 1 || changeto_val == 'y') {
		img.src = '/ava/pix/icons/icon.med.checkbox-check.gif';
		formvar_e.value = changeto_val;
	}
	else if (changeto_val == 0 || changeto_val === 0 || changeto_val == 'n') {
		img.src = '/ava/pix/icons/icon.med.checkbox-blank.gif';
		formvar_e.value = changeto_val;
	}	
}

function check_toggle (e) {
	f = document.getElementById(e);
	if (!f) {
		f = document.getElementsByName(e);
		if (f[0]) f = f[0];
	}

	if (f) {
		if (f.checked) f.checked = false;
		else f.checked = true;
	}
}

function check_on (e) {
	f = document.getElementById(e);
	if (!f) {
		f = document.getElementsByName(e);
		if (f[0]) f = f[0];
	}

	if (f) f.checked = true;
}

function check_off (e) {
	f = document.getElementById(e);
	if (!f) {
		f = document.getElementsByName(e);
		if (f[0]) f = f[0];
	}

	if (f) f.checked = false;
}


function highlight_row (elt) {
	toggle_css_class(elt,"row_highlight");
}

function add_css_class(elt, cls) {
	if (typeof(elt.className) != 'undefined') {
		remove_css_class(elt, cls);
		var newClasses = elt.className.split(" ");
		newClasses.push(cls);
		elt.className = newClasses.join(" ");
	}
}

function remove_css_class(elt, cls) {
	if (typeof(elt.className) != 'undefined') {
		var newClasses = new Array();
		var classes = elt.className.split(" ");
		for (var i = 0; i < classes.length; i++) {
			if (classes[i] != cls)
				newClasses.push(classes[i]);
		}
		elt.className = newClasses.join(" ");
	}
}

function has_css_class(elt, cls) {
	var hasClass = false;
	if (typeof(elt.className) != 'undefined') {
		var classes = elt.className.split(" ");
		for (var i = 0; i < classes.length; i++) {
			if (classes[i] == cls)
				hasClass = true;
		}
	}
	return hasClass;
}

function toggle_css_class(elt, cls) {
	if (has_css_class(elt, cls))
		remove_css_class(elt, cls);
	else
		add_css_class(elt, cls);
}