同步javascript不起作用

Question

我有一个脚本，可以生成一个音频文件数组，只需点击一下按钮即可播放。我试图使用同步JS来改变一些全局变量的值，并一直在测试带有警报的变化，但结果是“未定义”（或者我的弹出窗口没有显示）。

我的代码：

jQuery.ajaxSetup({async:false});
var s;
var group;

var curr_rec;
var curr_start = 1;
var curr_end;
var curr_s_obj;

var recs;
var sync = new Array();
var sync_group = new Array();

var check_rec;
var check_id;
var check_start;
var check_end;
var loaded = 0;

var s_obj;

function compare(a,b){
    if(a.fields.start_time<b.fields.start_time)
        return -1;
    if(a.fields.start_time>b.fields.start_time)
        return 1;
    return 0;
}

function process_data(recs){

    for(var i=0;i<recs.length;i++){
        check_rec = recs[i];
        check_id = check_rec.fields.file_ID;
        check_start = check_rec.fields.start_time;
        check_end = check_rec_fields.end_time;

        if((curr_start.getTime() <= check_start.getTime() && check_end.getTime()<= curr_end.getTime()) || 
            (curr_start.getTime()>=check_start.getTime() && curr_start.getTime()<=check_end.getTime()) || 
            (curr_end.getTime()>=check_start.getTime() && curr_end.getTime()<=check_end.getTime())
        )

        {
            //diff = (check_start.getTime() - curr_start.getTime())/1000;
            //check_rec["difference"] = diff;
            sync.push(check_rec);
        }
    }

}

function load_data(sync){

    var diff;
    var last = sync[sync.length-1];

    for(var j=0;j<sync.length-1;j++){
        s_obj = new buzz.sound(sync[i].fields.rec_file);
        sync_group.push(s_obj);
        diff = (last.fields.start_time.getTime() - sync[i].fields.start_time.getTime())/1000;
        if(diff>=0){
            s_obj.setTime(diff);
        }

        else{
            alert("error");
        }

    }

    loaded = 1;

}

function synchronise(id){

    $.ajax({
        type:"GET",
        url:"/webapp/playSound:" + id,

        success: function(data){
            curr_rec = eval("(" + data + ")");
            curr_start = curr_rec.fields.start_time;
            curr_end= curr_rec.fields.end_time;
            curr_s_obj = new buzz.sound(curr_rec.fields.rec_file);
    });
    alert("ggo");

    $.ajax(
        type:"GET",
        url:"/webapp/getRecs",

        success: function(data){
            recs = eval("("+ data +")");
            process_data(recs);

        });
    alert(curr_start);
    sync = sync.sort(compare);

    load_data(sync);


    var s1 = new buzz.sound( "../../static/data/second_audio.ogg");
    s = new buzz.sound( "../../static/data/" + id +".ogg"); //curr_rec.fields.rec_file

    /*
    sync_group.push(s);
    s.setTime(20.5);
    sync_group.push(s1);
    */

    group = new buzz.group(sync_group);
}

function playS(id){
    if(loaded==0)
        synchronise(id);
    group.togglePlay();
}

function stopS(){
    group.stop();
}