function checkvalid(obj)
{

   if(obj.UserName.value=="" || obj.PassWord.value=="")
    {
        alert ("用户名和密码不能为空！");
        obj.UserName.focus();
                return false;
    }

    if(obj.act_string.value==""){
        alert ("请输入验证码！");
        obj.act_string.focus();
        return false;
    }
        return true;
}

function CheckUser(obj){
        var uid;
        var userPassword;

        uid          =obj.UserName.value;
        userPassword =obj.PassWord.value;

        RequeryUrl="http://192.168.1.50/edu/null.php";

        var UequeryObj = new ActiveXObject("Microsoft.XMLHTTP")
        UequeryObj.open("POST",RequeryUrl,false,uid,userPassword)
        UequeryObj.send();

    switch(UequeryObj.status){

                case 200:

                        if (obj.identify.value=="stu")
                            document.location.href="../personal/student/";
                        else if (obj.identify.value=="tea")
                            document.location.href="../personal/teacher/";
                        else if (obj.identify.value=="edu")
                            document.location.href="../edu/";
                        else
                            alert("缺少属性！");

                        break;

                case 401:

                        alert("用户名或密码错误");

                        break;

                case 404:

                        alert("用户服务器错误");

                        break;

                default:

                        alert("发生未知错误");

                        break;

    }
}