function check_idcard($id)
{
    $id = strtoupper($id);
    $regx = "/(^\d{15}$)|(^\d{17}([0-9]|X)$)/";
    $arr_split = array();
    if (!preg_match($regx, $id)) {
            return FALSE;
        }
    if (15 == strlen($id)) //检查15位 
        {
            $regx = "/^(\d{6})+(\d{2})+(\d{2})+(\d{2})+(\d{3})$/";

            @preg_match($regx, $id, $arr_split);
            //检查生日日期是否正确 
            $dtm_birth = "19" . $arr_split[2] . '/' . $arr_split[3] . '/' . $arr_split[4];
            if (!strtotime($dtm_birth)) {
                    return FALSE;
                } else {
                return TRUE;
            }
        } else      //检查18位 
        {
            $regx = "/^(\d{6})+(\d{4})+(\d{2})+(\d{2})+(\d{3})([0-9]|X)$/";
            @preg_match($regx, $id, $arr_split);
            $dtm_birth = $arr_split[2] . '/' . $arr_split[3] . '/' . $arr_split[4];
            if (!strtotime($dtm_birth)) //检查生日日期是否正确 
                {
                    return FALSE;
                } else {
                    //检验18位身份证的校验码是否正确。 
                    //校验位按照ISO 7064:1983.MOD 11-2的规定生成，X可以认为是数字10。 
                    $arr_int = array(7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2);
                    $arr_ch = array('1', '0', 'X', '9', '8', '7', '6', '5', '4', '3', '2');
                    $sign = 0;
                    for ($i = 0; $i < 17; $i++) {
                            $b = (int)$id{
                            $i};
                            $w = $arr_int[$i];
                            $sign += $b * $w;
                        }
                    $n = $sign % 11;
                    $val_num = $arr_ch[$n];
                    if ($val_num != substr($id, 17, 1)) {
                            return FALSE;
                        } //phpfensi.com 
                    else {
                            return TRUE;
                        }
                }
        }
}