将数组转换成json格式(超牛)

function Item(){
this.programFolder=new Object();
this.programSite=new Object();
this.materialFolder=new Object();
this.materialSite=new Object();
}
var str = "({test:{programFolder:11, programSite:22, materialFolder:33, materialSite:44}})";
var a={};
a["test"]=new Item();
a.test.programFolder=11;
a.test.programSite=22;
a.test.materialFolder=33;
a.test.materialSite=44;

function obj2str(o){
    var r = [];
    if(typeof o =="string") return "\""+o.replace(/([\'\"\\])/g,"\\$1").replace(/(\n)/g,"\\n").replace(/(\r)/g,"\\r").replace(/(\t)/g,"\\t")+"\"";
    if(typeof o == "object"){
        if(!o.sort){
            for(var i in o)
                r.push(i+":"+obj2str(o[i]));
            if(!!document.all && !/^\n?function\s*toString\(\)\s*\{\n?\s*\[native code\]\n?\s*\}\n?\s*$/.test(o.toString)){
                r.push("toString:"+o.toString.toString());
            }
            r="{"+r.join()+"}";
        }else{
            for(var i =0;i<o.length;i++){
                r.push(obj2str(o[i]));
            }
            r="["+r.join()+"]";
        }
        return r;
    }
    return o.toString();
}
$(document).ready(function(){
$('#test').click(function(){
var b = eval(str);
alert(obj2str(b));
});
})