Bootstrap Transparent Jumbotron

by Grobbert

HTML

<script src="https://code.jquery.com/jquery-3.4.1.slim.js"></script>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.16.0/umd/popper.js"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/js/bootstrap.js"></script>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.css">

<nav class="navbar navbar-expand-lg navbar-light fixed-top">
  <a class="navbar-brand" href="#">Hello Dear</a>
  <button class="navbar-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 <span class="sr-only">(current)</span></a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">Link</a>
      </li>
      <li class="nav-item dropdown">
        <a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
          Dropdown
        </a>
        <div class="dropdown-menu" aria-labelledby="navbarDropdown">
          <a class="dropdown-item" href="#">Action</a>
          <a class="dropdown-item" href="#">Another action</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="#">Something else here</a>
        </div>
      </li>
      <li class="nav-item">
        <a class="nav-link disabled" href="#" tabindex="-1" aria-disabled="true">Disabled</a>
      </li>
    </ul>
    <form class="form-inline my-2 my-lg-0">
      <input class="form-control mr-sm-2" type="search" placeholder="Search" aria-label="Search">
    ...

CSS

.jumbotron {
    position: relative;
    background:none;
}
.jumbotron:after {
    content : "";
    display: block;
    position: absolute;
    top: 0;
    left: 0;
    background-image: url(https://cdn.pixabay.com/photo/2014/01/30/01/36/girl-254708_960_720.jpg);
    background-repeat: no-repeat;
    background-position: center;
    background-size: cover;
    width: 100%;
    height: 100%;
    opacity : 0.2;
    z-index: -1;
}

JavaScript

$(document).ready(function() {


$(window).scroll(function() {    
    var scroll = $(window).scrollTop();

     //>=, not <=
    if (scroll >= 60) {
        //clearHeader, not clearheader - caps H
        $(".navbar").addClass("bg-light");
    } else {
      $(".navbar").removeClass("bg-light");
    }
}); //missing );
  
// document ready  
});