IP整数相互转换

function IP2Num(ip)   
{  
    var num = 0;  
    ip = ip.split(".");  
    num = Number(ip[3]) * 256 * 256 * 256 + Number(ip[2]) * 256 * 256 + Number(ip[1]) * 256 + Number(ip[0]);  
    num = num >>> 0;  
    return num;  
} 

function Num2IP(num)   
{  
    var str;  
    var tt = new Array();  
    tt[0] = (num >>> 24) >>> 0;  
    tt[1] = ((num << 8) >>> 24) >>> 0;  
    tt[2] = (num << 16) >>> 24;  
    tt[3] = (num << 24) >>> 24;  
    str = String(tt[3]) + "." + String(tt[2]) + "." + String(tt[1]) + "." + String(tt[0]);  
    return str;  
}