如何用js定义数组，用js来拼接json字段

定义js数组的方式有：

var arr = ();
var arr = [];
var arr = new Array();

如何拼接成一个json字段。

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
 <HEAD>
  <TITLE> obj TO JSON Demo </TITLE>
  <META NAME="Generator" CONTENT="EditPlus">
  <META NAME="Author" CONTENT="">
  <META NAME="Keywords" CONTENT="">
  <META NAME="Description" CONTENT="">
 </HEAD>
<SCRIPT type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></SCRIPT>
<script type="text/javascript" src="js/jquery.json-2.4.min.js"></script>
 <BODY>
 <h2>利用jquery-json将js对象转化为JSON床</h2>
 <INPUT TYPE="button" VALUE="生成JSON串" ONCLICK="" id="testBut"><br/>
 <div id="showDiv" style="display:none">

 <div>
 </BODY>
 <script type="text/javascript">
    function student(sid,name,age,classInfo){
        this.sid=sid;
        this.name=name;
        this.aeg=age;
        this.classInfo=classInfo;
    }
    function classInfo(classname,teacher){
        this.classname=classname;
        this.teacher=teacher;
    }
    $(function(){
        $("#testBut").click(function(){
            var students = new Array();
                arry = new classInfo(‘三年级一班‘,‘项正伟‘);
                students[0]=new student(2014001,‘蔡子旭‘,23,arry);
                students[1]=new student(2014002,‘张苞‘,24,arry);
                students[2]=new student(2014003,‘张颌‘,33,arry);
            var jsonStr=$.toJSON(students);
            $("#showDiv").show();
            $("#showDiv").text(jsonStr);

        });
    });
 </script>
</HTML>