不同步做。使用回调。这里是一个演示给你： http://jsfiddle.net/s368a/1/

Don't do it synchronously. Use the callback. Here is a demo for you: http://jsfiddle.net/s368a/1/

<ul class="quoteList"></ul>
<input type="button" onclick="getData();" value="Go Get It!">

<script>
var counter = 0;

function getData()
{
    $.ajax({
        url:'http://whisperingforest.org/js/getQuote.php',
        async: true,
        dataType: 'jsonp',
        success:function(data){
            $('.quoteList').append('<li>' + data +'</li>');
            counter++;
            if (counter < 5) getData();
        }
    });
}
</script>

设置异步假块主线程（负责执行的JavaScript，呈现在屏幕等），并等待XHR完成。

Setting async to false blocks the main thread (responsible for executing JavaScript, rendering the screen, etc) and waits for the XHR to complete.

这是几乎总是一个可怕的想法。用户不喜欢没有响应的用户界面。 （http://***.com/a/20209180/3112803)

This is almost always a terrible idea. Users don't like unresponsive UIs. (http://***.com/a/20209180/3112803)

只要搜索计算器的 AJAX异步：假，你会发现这么多很好的解释。每个人都和他们的兄弟与鼓励你使用异步：假。这里是一个很好的解释：http://***.com/a/14220323/3112803

Just search *** for ajax async: false and you will find MANY good explanation on this. Everyone and their brother with discourage you from using async:false. Here's is a great explanation: http://***.com/a/14220323/3112803