How to make a floating menu and that change of style according to movement to scroll?

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2

How to make the scrolling fixed menu scrolling like that of the site:

link

Note that when you scroll, the background of the menu changes to black.

    
asked by anonymous 13.12.2018 / 23:41

1 answer

1

With a simple jQuery you do that. In this example when the person scrolls the 40px screen I'm going to put a .ativo class in Navbar with id menu . When it rolls back I retreat the class .ativo .

Seetheexampletounderstandbetter.IusedBootstrap4sinceyouputtheBootstraptag,butitworksonanycode,aslongasithasjQuerylikeBootstrap

TheonlyCSSincludedistostylenavtolooksimilartotheexample.

OBS:Ileftcommentsinthecodetomakeiteasiertounderstand

$(window).scroll(function() {    
var scroll = $(window).scrollTop();
  if (scroll >= 40) {               // se rolar 40px ativa o evento
    $("#menu").addClass("ativo");    //coloca a classe "ativo" no id=menu
  } else {
    $("#menu").removeClass("ativo"); //se for menor que 40px retira a classe "ativo" do id=menu
  }
});
body {
  min-height: 75rem;
  padding-top: 7.5rem;
  background-image: url(https://unsplash.it/400/200?image=6);
  background-size: cover;
  background-position: center;
  margin: 0;
}

#menu {
  background-color: rgba(0,0,0,0.2) !important;
  padding: 1.5rem 1rem;
  transition: all 500ms linear;
}
#menu.ativo {
  background-color: rgba(0,0,0,0.8) !important;
  padding: .5rem 1rem;
}
<link rel="stylesheet" type="text/css" media="screen" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" />
<script src="https://code.jquery.com/jquery-3.2.1.min.js"></script><scriptsrc="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"></script><navid="menu" class="navbar navbar-expand-md navbar-dark fixed-top bg-dark">
    <a class="navbar-brand" href="#">Fixed navbar</a>
    <button class="navbar-toggler collapsed" type="button" data-toggle="collapse" data-target="#navbarCollapse"
        aria-controls="navbarCollapse" aria-expanded="false" aria-label="Toggle navigation">
        <span class="navbar-toggler-icon"></span>
    </button>
    <div class="navbar-collapse collapse" id="navbarCollapse">
        <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">
                <a class="nav-link disabled" href="#">Disabled</a>
            </li>
        </ul>
    </div>
</nav>

<main role="main" class="container">
    <div class="jumbotron">
        <h1>Navbar example</h1>
        <p class="lead">This example is a quick exercise to illustrate how fixed to top navbar works. As you
            scroll, it will remain fixed to the top of your browser's viewport.</p>
        <a class="btn btn-lg btn-primary" href="../../components/navbar/" role="button">View navbar docs »</a>
    </div>
</main>
    
13.12.2018 / 23:56
Convert string positions to integer Iteration using "while"