Web开发中Javascript校验IP是否属于指定的网段

Web开发中通常会有很多数据需要校验，有时一些校验不是一句简单的正则表达式能搞定的，需要复杂的计算规则，例如最近遇到了一个较为复杂的数据校验，当我们输入一个IP地址的时候需要检验这个IP地址是否属于我们所指定的子网内，下面的code是自己写的一个较为粗糙的一个校验方法，以后有时间还会继续重构一下。

function ValidateIPRange(subnet, netmask){
/**
* subnetBin: 子网的二进制表示
* netmaskBin: 子网掩码的二进制表示
* networkLength: 子网的网络地址长度
* subnetNetBit: 子网的网络地址位二进制表示
* subnetHostBit: 子网的主机地址二进制表示
* broadcastHostBit: 广播地址二进制表示
*/
var subnetBin = _ipToBin(subnet);
var netmaskBin = _ipToBin(netmask);
var networkLength = _getNetworkLength();
var subnetNetBit = "";
var subnetHostBit = "";
var broadcastHostBit = "";

//判断目标IP是不是属于指定的子网内
this.isInRange = function(targetIP){
this.getNetwork()
var targetIPNetworkBin = _ipToBin(targetIP);
var targetIPNetBit = targetIPNetworkBin.substr(0, networkLength);
var targetIPHostBit = targetIPNetworkBin.substr(networkLength);
//排除网络地址与广播地址
if(targetIPNetBit == subnetNetBit && targetIPHostBit != subnetHostBit && targetIPHostBit != broadcastHostBit){
return true;
}else{
return false;
}
}

this.getNetwork = function(){
var networkBin = _andOpration(subnetBin, netmaskBin);
subnetNetBit = networkBin.substr(0, networkLength);
subnetHostBit = networkBin.substr(networkLength);
broadcastHostBit = subnetHostBit.replace(/0/g, "1");
return _binToIp(networkBin);
}

this.getBroadcast = function(){
this.getNetwork();
var broadcastBin = subnetNetBit + broadcastHostBit;
return _binToIp(broadcastBin);
}

function _getNetworkLength(){
var length = 0;
for(var i = 0; i < 32; i++){
if(netmaskBin.charAt(i) == "1"){
length++;
}else{
break;
}
}
return length;
}

function _andOpration(ipBin, netmaskBin){
var result = "";
for(var i = 0; i < 32; i++){
result += (parseInt(ipBin.charAt(i)) & parseInt(netmaskBin.charAt(i)));
}
return result;
}

function _ipToBin(ip){
var subIpArray = ip.split(".");
var ipBin = "";
for(var i = 0; i < subIpArray.length; i++){
ipBin += _binCompletion(parseInt(subIpArray[i]).toString(2));
}
return ipBin;
}

function _binToIp(bin){
var ip = "";
for(var i = 0; i < bin.length; i += 8){
ip += ("." + parseInt(bin.substr(i, 8), 2));
}
ip = ip.substr(1);
return ip;
}

function _binCompletion(subBin){
var complBin = subBin;
if(subBin.length < 8){
var length = subBin.length;
for (var i = 0; i < (8 - length); i++)
{
complBin = "0" + complBin;
}
}
return complBin;
}

//ip2number和number2ip是在网上找到的更简洁的方法，需要一点算法基础
function ip2number(ip) {
var tokens = ip.split('.');
var numval = 0
for (num in tokens) {
numval = (numval << 8) + parseInt(tokens[num]);
}
return numval
}

function number2ip(number) {
byte1 = number & 0xff;
byte2 = (number & 0xff00);
byte2 >>>= 8;
byte3 = (number & 0xff0000);
byte3 >>>= 16;
byte4 = (number & 0xff000000);
byte4 >>>= 24;
var result = byte4 + "." + byte3 + "." + byte2 + "." + byte1;
return result;
}
}

var validate = new ValidateIPRange("172.17.16.0", "255.255.0.0");
alert(validate.isInRange("172.17.16.4"));
alert(validate.getNetwork());
alert(validate.getBroadcast());