js 如何获取硬盘序列号呢？找了很久没找到合适的

 　var locator = new ActiveXObject ("WbemScripting.SWbemLocator");
　　　var service = locator.ConnectServer(".");
　　　var properties = service.ExecQuery("SELECT * FROM Win32_DiskDrive");
　　　var e = new Enumerator (properties);
　　　document.write("<table border=1>");
　　　for (;!e.atEnd();e.moveNext ())
　　　{
　　　　　　var p = e.item ();
　　　　　　document.write("<tr>");
　　　　　　document.write("<td>" + p.signature + "</td>");
　　　　　　document.write("</tr>");
　　　}

网上大部分是这样写的 但是获取的不对 大部分台式机根本获取不到 大家有什么好办法吗？

    var locator = new ActiveXObject("WbemScripting.SWbemLocator");
    var service = locator.ConnectServer(".");
    var properties = service.ExecQuery("SELECT * FROM Win32_PhysicalMedia");
    var e = new Enumerator(properties);
    document.write("<table border=1>");
    for (; !e.atEnd() ; e.moveNext()) {
        var p = e.item();
        if (p.SerialNumber) {
            document.write("<tr>");
            document.write("<td>" + p.SerialNumber + "</td>");
            document.write("</tr>");
        }
    }

//注意 在 IE浏览器下打开 ActiveXObject 兼容

window.onload = function(){
var info = JSON.stringify(getSysInfo());
alert(info);
}

function getSysInfo(){
var locator = new ActiveXObject ("WbemScripting.SWbemLocator");
var service = locator.ConnectServer(".");
//CPU信息
var cpu = new Enumerator (service.ExecQuery("SELECT * FROM Win32_Processor")).item();
var cpuType=cpu.Name,hostName=cpu.SystemName;
//内存信息
var memory = new Enumerator (service.ExecQuery("SELECT * FROM Win32_PhysicalMemory"));
for (var mem=[],i=0;!memory.atEnd();memory.moveNext()) mem[i++]={cap:memory.item().Capacity/1024/1024,speed:memory.item().Speed}
//系统信息
var system=new Enumerator (service.ExecQuery("SELECT * FROM Win32_ComputerSystem")).item();
var physicMenCap=Math.ceil(system.TotalPhysicalMemory/1024/1024),curUser=system.UserName,cpuCount=system.NumberOfProcessors

var properties = service.ExecQuery("SELECT * FROM Win32_DiskDrive");

　　var p = new Enumerator (properties).item();
return {cpuType:cpuType,cpuCount:cpuCount,hostName:hostName,curUser:curUser,memCap:physicMenCap,mem:mem,num:p.signature }
}