javascript判断两个IP地址是否在同一个网段的实现思路

实现IP地址判断是否在同一个网段，可以使用Javascript实现的思路如下：

1. 首先将IP地址转换成二进制格式，方便进行比较，然后将子网掩码也转换成二进制格式。

2. 对转换后的IP地址和子网掩码进行&（与运算），得到的结果就是该IP地址所在的网络地址。

3. 将要比较的两个IP地址按照以上步骤进行转换得到两个网络地址。

4. 比较两个网络地址是否相同，如果相同，则说明这两个IP地址在同一个网络。

下面是两个示例说明：

示例1：判断10.0.0.10和10.0.0.15是否在同一个网络中，子网掩码为255.255.255.0。

function isSameNetwork(ip1, ip2, subnetMask) {
  const ip1Binary = ipToBinary(ip1);
  const ip2Binary = ipToBinary(ip2);
  const subnetMaskBinary = ipToBinary(subnetMask);

  const network1 = ip1Binary & subnetMaskBinary;
  const network2 = ip2Binary & subnetMaskBinary;

  return network1 === network2;
}

function ipToBinary(ipAddress) {
  const parts = ipAddress.split(".");
  const binaryParts = parts.map(part => {
    const binary = parseInt(part, 10).toString(2);
    return "00000000".substr(binary.length) + binary;
  });
  return binaryParts.join("");
}

const ip1 = "10.0.0.10";
const ip2 = "10.0.0.15";
const subnetMask = "255.255.255.0";

if (isSameNetwork(ip1, ip2, subnetMask)) {
  console.log(`${ip1} and ${ip2} are in the same network.`); // 输出10.0.0.10 and 10.0.0.15 are in the same network.
} else {
  console.log(`${ip1} and ${ip2} are not in the same network.`); 
}

示例2：判断192.168.1.100和192.168.2.100是否在同一个网络中，子网掩码为255.255.255.0。

function isSameNetwork(ip1, ip2, subnetMask) {
  const ip1Binary = ipToBinary(ip1);
  const ip2Binary = ipToBinary(ip2);
  const subnetMaskBinary = ipToBinary(subnetMask);

  const network1 = ip1Binary & subnetMaskBinary;
  const network2 = ip2Binary & subnetMaskBinary;

  return network1 === network2;
}

function ipToBinary(ipAddress) {
  const parts = ipAddress.split(".");
  const binaryParts = parts.map(part => {
    const binary = parseInt(part, 10).toString(2);
    return "00000000".substr(binary.length) + binary;
  });
  return binaryParts.join("");
}

const ip1 = "192.168.1.100";
const ip2 = "192.168.2.100";
const subnetMask = "255.255.255.0";

if (isSameNetwork(ip1, ip2, subnetMask)) {
  console.log(`${ip1} and ${ip2} are in the same network.`); 
} else {
  console.log(`${ip1} and ${ip2} are not in the same network.`); // 输出192.168.1.100 and 192.168.2.100 are not in the same network.
}

这是基本的实现思路，根据实际情况还可能需要做一些优化，例如处理各种IP地址格式、检查输入的子网掩码是否合法等。