小编Irs*_*haq的帖子

我有使用Bootstrap 4的html代码。就我而言，当导航栏切换按钮单击时，导航栏会自动打开和隐藏。单击时如何手动打开和隐藏导航栏？谢谢任何人。

<title>SuperEvent</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" type="text/css" href="css/style.css">
<link rel="stylesheet" type="text/css" href="css/bootstrap.css">
<link rel="stylesheet" type="text/css" href="https://cdnjs.cloudflare.com/ajax/libs/animate.css/3.5.2/animate.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
<script type="text/javascript" src="js/script.js"></script>

<div class="header">
  <div class="container">   
    <div class="row">
      <div class="col-md-12 col-sm-12 col-xs-12">
        <img src="img/iklan.JPG" class="iklan float-right">
      </div>
    </div>
    <div class="cleafix"></div>
    <nav class="navbar navbar-expand-lg " id="nav" >
    <a class="navbar-brand" href="#">Super Event</a>
    <button class="navbar-toggler custom-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
        <span class="navbar-toggler-icon"></span>
      </button>
      <div class="collapse navbar-collapse" id="navbarSupportedContent">
        <ul class="navbar-nav mr-auto">
          <li class="nav-item active">
            <a class="nav-link" href="#">Home …

我有两个收藏user和transaction. 我想要获取user不在exists集合中的记录transaction。然后我就这样做

[
    {
       "$lookup" : {
            "from" : "transaction",
            "localField":"_id",
            "foreignField":"user",
            "as" : "trans"
       }
   },
   {
       "$match": { "transaction.user": { "$exists": false } }
   },
   {"$limit":20}
]

但我没有记录我想要的东西。