jQuery Ajax返回NULL

I have a little script to request json data from my database. Here is the Code

    <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.0/jquery.min.js"></script>
<script type="text/javascript">
$(function() {
    $(document).ready(function() {
        var keyword = "1";
         var baseurl1 = "json_data2.php?l=" + keyword;
        // Product Count 
        var json = (function() {
            var json = null;
            $.ajax({
                'async': false,
                'global': false,
                'url': baseurl1,
                'dataType': "json",
                'success': function(data) {
                    json = data;
                }
            });
            return json;
        })();
        console.log(json);

    });
});
</script>

When my Feed looks like this

{"limit": [{"rows":"127"}]}

I get "Object {limit: Array[1]}" in the console. So it seems to word. I can also alert json.limit[0].rows and get 127 shown. So far so good.

When I try to get another feed of data which looks like this

{"posts": [{"productname":"Das kleine Ich bin ich","link":"if3OHlvncaIY7A7VGze7VSIeAAZAIZV83cvaG%2B5w3U48cuooMp9qZZJkdQzwyGEXgk8LCR9kD7nY6Y%2FSR0RnjRJo44jHguoaesLAa4mLhuKpuLsfty85ZaePH%2FHReJTc","imgurl":"img\/products\/mytoys\/das-kleine-ich-bin-ich.jpg","price":"13.90","oldprice":"","sale":""},]}

the console log shows up with "null". What could be the issue? I mean I change nothing on the code, just the Url. The datafeed is JSON and I also visited the datafeed in my browser, it's showing up correctly. Any pointers?

console.log logs null because when that line is executed, ajax execution hasn't finished yet, your console log, and whatever you want to do with data that is being returned by your ajax call MUST be inside the success callback