var errmes = "";

function display_errors() {
	alert(errmes);
	errmes = "";
	}

function report_type_error(group, name) {
	errmes += "the value for " + name + " in the group " + group + " is not valid.\n";
	}

function report_bound_error(group, name) {
	errmes += "the value for " + name + " in the group " + group + " is out of bounds.\n";
	}

function report_missing_error(group, name) {
	errmes += "the field " + name + " in group " + group + " cannot left be empty.\n";
	}

function report_form_error(s) {
	errmes += s;
	}

function check_string(s, group, name) {
	if (s.length == 0) {
		report_missing_error(group, name);
		return false;
		}
	return true;
	}

function check_int(val, group, name) {
	if (check_string(val, group, name) == false)
		return false;
	if (isNaN(parseInt(val))) {
		report_type_error(group, name);
		return false;
		}
	return true;
	}

function check_float(val, group, name) {
	if (check_string(val, group, name) == false)
		return false;
	if (isNaN(parseFloat(val))) {
		report_type_error(group, name);
		return false;
		}
	return true;
	}

function check_bfloat(val, group, name, low, high) {
	var v = parseFloat(val);
	if (isNaN(v)) {
		report_type_error(group, name);
		return false;
		}
	if ((v < low) || (v > high)) {
		report_bound_error(group, name);
		return false;
		}
	return true;
	}