// function that checks, that field of form is filled out
function filled (field, message) {
	if (field.value == "") {
		alert(message);
		return false;
	}
	else
		return true;
}

// check, that password fields are equal
function passEqual (pass1, pass2, message) {
	if (pass1.value != pass2.value) {
		alert(message);
		return false;
	}
	else
		return true;
}

// returns element with given id 
function getElement (elementid) {
	var elm = null;
	if (document.getElementById) 
		elm = document.getElementById(elementid); 
	else if (document.all) 
		elm = document.all[elementid];
	return elm;
}

// test, whether papametr is a number or not
function isNumber(field, msg) {
	if (isNaN(field.value)) {
		alert(msg);
		field.focus();
		field.select();
		return false;
	}
	else
		return true;
}

// test integer
function isInteger(field, msg) {
	if (isNaN(field.value)) {
		alert(msg);
		field.focus();
		field.select();
		return false;
	}
	else {
		field.value = parseInt(field.value,10);
		return true;
	}
}