身份证号码格式验证

From: https://www.cnblogs.com/chenhaoyu/p/6189207.html

/**
 * 验证身份证号码真伪
 * @param $id
 * @return bool
 */
function checkIDCard( $id )
{
	$id = strtoupper($id);
	$regx = '/(^\d{15}$)|(^\d{17}([0-9]|X)$)/';
	if(!preg_match($regx, $id))
		return false;

	$arr_split = [];
	if(15 == strlen($id))
	{
		$regx = '/^(\d{6})+(\d{2})+(\d{2})+(\d{2})+(\d{3})$/';
		@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
	{
		$regx = '/^(\d{6})+(\d{4})+(\d{2})+(\d{2})+(\d{3})([0-9]|X)$/';
		@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;

		// 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 = [7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2];
		$arr_ch = ['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;
	}

	return true;
}