function validate(f) {
var str = "";
var color = '#FF0000';
var elements = f.elements;
for(var i = 0; i < elements.length; i++) {
	var pattern = elements.item(i).getAttribute('pattern');
	if (pattern != null) {
		var value = elements.item(i).value;
		var re = new RegExp(pattern);
		if( !re.test(value) ) {
			str += elements.item(i).getAttribute('errorMsg') + "\n";
			elements.item(i).style.background = color;
		}
	}
}

if (str != "") {
	alert("At filling the form some mistakes have been admitted:\n" + str);
	return false;
}
else {
	return true;
}
}

function changeColor(th) {
	th.style.background = '#FFFFFF';
}