function ElById(idName)
{
	return document.getElementById(idName);
}

function showErrorFor(idName, msg)
{
	if (msg == false)
	{
		ElById('err_'+idName).style.display = 'none';
		ElById('err_'+idName).innerHTML = '';
		ElById(idName).style.borderColor = 'green';
	}
	else
	{
		ElById('err_'+idName).style.display = 'block';
		ElById('err_'+idName).innerHTML = msg;
		ElById(idName).style.borderColor = 'red';
	}
}


function toggleError(idName, msg)
{
	if (!msg)
	{
		ElById(idName).style.borderColor = 'green';
	}
	else
	{
		ElById(idName).style.borderColor = 'red';
	}
}


function isGroupChecked(idForm, groupIdPrefix)
{
  	var n = 0;
  	Frm = ElById(idForm);
  	for (i=0; i<Frm.elements.length; i++)
  	{
  		if (Frm.elements[i].id.indexOf(groupIdPrefix) !=-1 && Frm.elements[i].checked) n++;
  	}
  	
  	return n;
}


function getSelectedOption(idName)
{
	if (ElById(idName).length)
	{
		o = ElById(idName).options[ElById(idName).selectedIndex];
		if (o) return o.value;
		else return false;
	}
	else return false;
}


function checkEmailFormat(mail_address)
{
  ParsePetrn = /[a-z_0-9\.]+[-]*[a-z_0-9\.]*[@][a-z_0-9\.]+[-]*[a-z_0-9\.]+[.]\w+[.]\w+|[a-z_0-9\.]+[-]*[a-z_0-9\.]*[@][a-z_0-9\.]+[-]*[a-z_0-9\.]+[.]\w+/i
  return ParsePetrn.test(mail_address);
}