JS中IP地址与整数的相互转换

function ipToNumber(ip) {
var num = 0;
if(ip == "") {
return num;
}
var aNum = ip.split(".");
if(aNum.length != 4) {
return num;
}
num += parseInt(aNum[0]) << 24;
num += parseInt(aNum[1]) << 16;
num += parseInt(aNum[2]) << 8;
num += parseInt(aNum[3]) << 0;
num = num >>> 0;//这个很关键，不然可能会出现负数的情况
return num;
}

function numberToIp(number) {
var ip = "";
if(number <= 0) {
return ip;
}
var ip3 = (number << 0 ) >>> 24;
var ip2 = (number << 8 ) >>> 24;
var ip1 = (number << 16) >>> 24;
var ip0 = (number << 24) >>> 24

ip += ip3 + "." + ip2 + "." + ip1 + "." + ip0;

return ip;
}