Php Jquery UI自动完成有问题

我的php代码是这样的

if (isset($_REQUEST['term']))
{
    $term = trim(strip_tags($_REQUEST['term']));//retrieve the search term that autocomplete sends

    $result = $db->query("SELECT company as value,id FROM main WHERE company LIKE '$term'") or die(mysqli_error());;
    $results = array();
    while ($row = $result->fetch_row()) $results[] = array( 'id' => $row[0] , 'label' => $row[1], 'value' => $row[1] );
    echo json_encode($results);
}

下面是Js代码

$("#auto").autocomplete({
    source: "index.php",
    minLength: 2,//search after two characters
    select: function(event,ui){
    }
});

和HTML标记

<input id="auto" name="company"/>

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代码怎么了？它不会生成自动完成选项。。php日志文件中没有错误。如何解决这个问题？

假设json正常，那么您就不会对返回的数据进行任何处理

select: function(event,ui){
// do something with the data you get back
//you would usually have a function here to do something with data
// but this sample should be enough for you 
var id = ui.id;  // id you got back assign to var
var label = ui.label; // label you got back assign to var
$('#gothisback').val(ui.id); //push it to a div
    }

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哪个部门？我想把它作为自动完成菜单拿回来