jquery autocomplete 不显示下拉列表

各位大神我做了一个jquery autocomplete的小程序，但是他为什么不显示下拉列表呢？求大神指教。
$(document).ready(function () {
var data=["我是厉害","天地大同","努力","去哪里","中关村一街","tencent","tom","我是干活广告"];

$("#lockGuid").autocomplete(data,{
max: 4,
scrollHeight: 200,
scroll: true,
width:50,
autoFill: true,
delay:10,
cacheLength:10
});