var xmlHttp;
createXMLHttpRequest();
function createXMLHttpRequest()
{
    //判断浏览器类型并创建对象
    //IE
    if (window.ActiveXObject)
    {
        xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
    }
    //FF
    else if (window.XMLHttpRequest)
    {
        xmlHttp = new XMLHttpRequest();
    }
}

//光标处于输入框时引发的动作
var type;
function updateLogin(tp)
{
    type = tp;    
    var now   = new Date(),
    y   = now.getFullYear(),
    month = now.getMonth()+1,
    d     = now.getDate(), 
    h   = now.getHours(),
    m   = now.getMinutes(),
    s   = now.getSeconds(),
    SS   = now.getMilliseconds(),
    time  = y+""+month+""+d+""+h+""+m+""+s;
    if (type == 1)
    {
        //登录验证信息是否为空
        if (!IsLogin())
            return false;
            
        var username = document.getElementById("txtUserName").value;
        var password = document.getElementById("txtPwd").value;
        url = "AjaxPage.aspx?type=" + type + "&UserName=" + username + "&Pwd=" + password+"&time="+time;
    }
    if (type == 0)
    {
        url = "AjaxPage.aspx?type=" + type+"&time="+time;
    }
    xmlHttp.open("GET",url,true);
    xmlHttp.onreadystatechange = doUpdate;
    xmlHttp.send();

    return false;
}

function doUpdate()
{
    if (xmlHttp.readyState == 4)
    {
        var str = xmlHttp.responseText;
        if (type == 1)
        {
            if (str == "fail")
            {
                alert("登录失败！");
                return false;
            }
            else
            {
                document.getElementById("divlogin").innerHTML = xmlHttp.responseText;
                //divlogin.innerHTML='<a href=\"#\" onclick=\"updateLogin(0)\">退出</a>&nbsp;&nbsp;|&nbsp;&nbsp;<a href=\"#\">帮助</a>';
            }
        }
        else if (type == 0)
        {
            if (str == "fail")
            {
                alert("退出失败！");
                return;
            }
            else
            {
                document.getElementById("divlogin").innerHTML = xmlHttp.responseText;
                //divlogin.innerHTML='<a href=\"Login.aspx\">登录</a>&nbsp;&nbsp;|&nbsp;&nbsp;<a href=\"Reg.aspx\">注册</a>&nbsp;&nbsp;|&nbsp;&nbsp;<a href=\"#\">帮助</a>';
            }
        }
    }
}

function IsLogin()
{
    var usernam = document.getElementById("txtUserName").value;
    var pasword = document.getElementById("txtPwd").value;
    if (usernam == "")
    {
        alert("请输入用户名！");
        return false;
    }
    if (pasword == "")
    {
        alert("请输入密码！");
        return false;
    }
    return true;
}

function EnterTextBoxUser()   
{
    if(event.keyCode == 13 && document.all["txtUserName"].value != "")
    {
        document.getElementById("txtPwd").focus();
      
    }   
}   

function EnterTextBoxPwd()   
{
    if(event.keyCode == 13)
    {
        updateLogin(1);

    }   
}