var check_field = function( field )
{
	if ( field.value.trim().length > 0 )
		$('join_form_username_check_button').disabled = false;
	else
		$('join_form_username_check_button').disabled = true;
}

var check_field_value = function()
{
	if ( $('join_profile_form_username').value.trim().length > 0 )
		return true;
	else
		return false;
}

var hide_chek_result = function()
{
	$('username_check_aj_div').style.display = 'none';
	$('username_check_div').innerHTML = '<input type="button" id="join_form_username_check_button" value="Check" onclick="xajax_checkUsername($(\'join_profile_form_username\').value);" />';
}