function filterUserID(oldval)
{
	newval = oldval;
	newval = newval.replace(/@.*$/, '');
	newval = newval.toLowerCase();
	newval = newval.replace(/[^a-z0-9-]/g, '');
	newval = newval.substr(0, 30);
	return newval;
}

function correctUserID(fld)
{
	newval = filterUserID(fld.value);
	if (newval != fld.value)
	{
		alert('User ID \'' + fld.value + '\' is not valid.\n' +
		'Another one close to it has\n' +
		'been substituted for you:\n\n' + newval);
		fld.value = newval;
	}
}