jquery自动完成小部件传递源参数

Question

我使用jquery自动完成小部件。 现在我想用这个自动完成小部件激活几个控件：

<div class="ui-widget">
    <label id="lbl0">City:</label><br />
    <input id="txt0" style="width: 25%;">
    <br /><br />
    <label id="lbl1">Fruit:</label><br />
    <input id="txt1" style="width: 25%;">
    <br /><br />
    <label id="lbl99">City:</label><br />
    <input id="txt99" style="width: 25%;">
    <br /><br />
    <label id="lbl100">Fruit:</label><br />
    <input id="txt100" style="width: 25%;">
</div>

对于每个控件，定义了要使用的数据：

// the sources we want to use (cities and fruits):
var sourceToUse = ['cities', 'fruits'];

JavaScript循环遍历定义并相应地填充控件。 在此示例中，定义放在名为“sourceToUse”的数组中（实际上，定义是从数据库中检索的）：

    $(function () {
       // the sources we want to use (cities and fruits):
       var sourceToUse = ['cities', 'fruits'];
       // populate the controls accordingly using a loop
       for (var i = 0; i <= sourceToUse.length; i++) {
            $("#txt" + i).autocomplete({
            source: function (request, response) { fSource(request, response, sourceToUse[i]) },
                    autoFocus: true,
                    delay: 500
            });
       }
       // populate without a loop
       $("#txt99").autocomplete({ source: function (request, response) { fSource(request, response, 'cities') } });
       $("#txt100").autocomplete({ source: function (request, response) { fSource(request, response, 'fruits') } });
   });

将参数值传递给的函数：

function fSource(request, response, sourceChosen) {
            // several sources to retrieve from (in a database)
            var cities = ["CAEN", "CALAIS", "CANNES", "CHAMPIGNY-SUR-MARNE", "CLERMOND-FERRAND"];
            var fruits = ["APPLE", "APRICOT", "ADVOCADO", "BLACKBERRY", "BLUEBERRY", ];
            var sourceToUse = [];
            var sourceToReturn = [];
            // a source is chosen to get its data from
            switch (sourceChosen) {
                case 'cities':
                    sourceToUse = cities;
                    break;
                case 'fruits':
                    sourceToUse = fruits;
                    break;
            }
            // return from the source chosen only that what has been asked for
            $.each(sourceToUse, function (index, value) {
                if (value.substring(0, request.term.length) == request.term) {
                    if ($.inArray(value, sourceToReturn) == -1) {
                        sourceToReturn.push(value);
                    }
                }
            });
            response(sourceToReturn);
        }

在使用循环时，参数“sourceChosen”的值不会传递给函数“fSource”。 在此示例中，数据来自数组“城市”或“水果”。 （实际上，数据是从数据库中检索出来的）如果我直接分配一个值就行了。 知道为什么传递参数不起作用？

看到这个Plunker： https ：//plnkr.co/edit/wEy5HC4tv4m1hwoQOheZ