你能在发帖前添加lastXhr.abort()吗？这将在你每次开始一个新的请求时取消以前的请求。

$(function() {
    var cache = {}, lastXhr;

    $('#Field').autocomplete({
        minLength: 2,
        delay: 600,
        source: function(request, response) {
            var term = request.term;

            if( term in cache ) {
                response(cache[term]);
                return;
            }

            // Abort previous access if one is defined
            if (typeof lastXhr !== 'undefined' && lastXhr.hasOwnProperty("abort")) {
                lastXhr.abort();
            }

            lastXhr = $.post('LoadData', function(data, status, xhr) {
                cache[term] = data;

                if(xhr === lastXhr) {
                    response(data);
                    // Set to undefined, we are done:
                    // helps when deciding to abort
                    lastXhr = undefined;
                }
            });
        }
    });
});

将最终结果与请求沿着缓存，这样就可以确保每次都调用响应回调，并且lastData将确保使用正确的数据，而不管查询返回时是否不同步。
例如：

$(function() {
    var cache = {}, lastXhr,lastData;

    $('#Field').autocomplete({
        minLength: 2,
        delay: 600,
        source: function(request, response) {
            var term = request.term;

            if( term in cache ) {
                response(cache[term]);
                return;
            }

            lastXhr = $.post('LoadData', function(data, status, xhr) {
                cache[term] = data;

                if(xhr === lastXhr) {
                    response(data);
                    // Store the latest data
                    lastData = data;

                }
                else
                {
                    // Queries have come back out of sync - this isn't the last one
                    // but we need to call response to stop the spinner
                    response(lastData);
                }
            });
        }
    });
 });

我只会说：

if(xhr === lastXhr) {
    response(data);
} else {
    return false;
}

您可以确保autocomplete只处理最后一个响应，方法是在响应中包含搜索字符串，并使用matchResponseProperty告诉autocomplete保存搜索字符串的json响应属性的名称。http://easyautocomplete.com/guide#sec-async