官网：http://jqueryui.com/autocomplete

最简单的形式：

var availableTags = [
"ActionScript",
"AppleScript",
"Asp",
"BASIC",
"C",
"C++",
"Clojure",
 
];
$( "#tags" ).autocomplete({
source: availableTags
});

数据源source有多种形式：

source:

Type: Array or String or Function( Object request, Function response( Object data ) )

Multiple types supported:

• Array: An array can be used for local data. There are two supported formats:
  • An array of strings: [ "Choice1", "Choice2" ]
  • An array of objects with label and value properties: [ { label: "Choice1", value: "value1" }, ... ]
  The label property is displayed in the suggestion menu. The value will be inserted into the input element when a user selects an item. If just one property is specified, it will be used for both, e.g., if you provide only valueproperties, the value will also be used as the label.
• String: When a string is used, the Autocomplete plugin expects that string to point to a URL resource that will return JSON data. It can be on the same host or on a different one (must provide JSONP). The Autocomplete plugin does not filter the results, instead a query string is added with a term field, which the server-side script should use for filtering the results. For example, if the source option is set to "http://example.com" and the user types foo, a GET request would be made to http://example.com?term=foo. The data itself can be in the same format as the local data described above.
• Function: The third variation, a callback, provides the most flexibility and can be used to connect any data source to Autocomplete. The callback gets two arguments:
  • A request object, with a single term property, which refers to the value currently in the text input.(输入框的值） For example, if the user enters "new yo" in a city field, the Autocomplete term will equal "new yo".
  • A response callback, which expects a single argument: the data to suggest to the user. This data should be filtered based on the provided term, and can be in any of the formats described above for simple local data. It‘s important when providing a custom source callback to handle errors during the request. You must always call the response callback even if you encounter an error. This ensures that the widget always has the correct state.

  When filtering data locally, you can make use of the built-in $.ui.autocomplete.escapeRegex function. It‘ll take a single string argument and escape all regex characters, making the result safe to pass to new RegExp().

Code examples:

Initialize the autocomplete with the source option specified:

Get or set the source option, after initialization:

 var  Cache=[];        var firstLoaded=true;    $(".input").autocomplete({        minLength:0,        source: Cache    }).focus(function(){         var that=$(this);                  if(firstLoaded)          {              var ret=[];              $.getJSON(‘url‘,{},function(data){              for(var i in data)              {                  ret.push(data[i]);              }                           Cache=ret;              firstLoaded=false;                           that.autocomplete({ source: Cache});//一定要重新载入              that.autocomplete(‘search‘);                               });          }          else          {              that.autocomplete(‘search‘);          }           });

 source: Cache指向的是引用，ajax更改了cache的值应该会起作用的，可是事与愿违，必须，重新调用

that.autocomplete({ source: Cache});方可起作用。

上面的例子也演示了如何当input获得焦点时立即显示自动完成。这里有2个关键字。

focus函数，调用autocomplete触发search，还有一点是设置maxLength为0，因为search函数Triggered before a search is performed, after minLength and delay are met. If canceled, then no request will be started and no items suggested.

jquery ui autoComplete自动完成