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How to make an element disappear and reappear when scrolling down?

So, on my website, I have a fixed bar at the top that covers the page length, the h1 panel. A mini-navigator with the "Back" and "Home" buttons, which are located below it and are also fixed, is connected to this. The mini navigator interferes with reading the contents of the page when scrolling down, so I would like the navigator to disappear when the user scrolls down, and also makes it possible to display it again by moving the mouse over the top / clicking on the top of the bar / scrolling the top bar on touch screen etc. etc.

How should I do it?

Here's the HTML:

<header class="mainHeader">
  <h1>Page Title</h1>
    <nav class="secondaryNav">
      <a href="home.htm"><img class="backButton" src="img/back2.png" alt="Back Button"></a>
      <a href="home.htm"><img class="homeButton" src="img/home.png" alt="Home Button"></a>
    </nav>
    <aside><p id="countdown"></p></aside>
</header>
<!-- end .mainHeader -->

And CSS:

.mainHeader h1 {
    position: fixed;
    top: 0;
    width: 100%;
    background: #ea594e;
    box-shadow: 0 0 3px 3px #888888;
    font-family: verdana;
    font-variant: small-caps;
    color: white;
    border-bottom: 1px solid black;
    margin: 0;
    padding-bottom: 0.5%;
    text-align: center;
}

.mainHeader .secondaryNav {
    background: #ffcda4;
    box-shadow: 0 3px 3px 1px #888888;
    border: 1px solid;
   border-top: none;
    width: 400px;
    position: fixed;
    top: 49px;
    left: 50%;
    margin-left: -200px;
    border-radius: 0 0 50px 50px;
    padding-top: 5px;
}

String h1, and the mini navigator is secondary

+4
3

scrollTop , ,

$(function() {
  $(document).on("mousewheel", function() {
    if($(document).scrollTop() > 100){
        $('.secondaryNav').show();
        $('.mainHeader h1').hide();
    } else {
        $('.secondaryNav').hide();
        $('.mainHeader h1').show();
    }; 
  });
});

Fiddle ( css, , )

0

u. JSFIDDLE

 //Keep track of last scroll
          var lastScroll = 0;
          $(window).scroll(function(event){
              //Sets the current scroll position
              var st = $(this).scrollTop();
              //Determines up-or-down scrolling
              if (st > lastScroll){
//secondaryNav disappears when scrolled down
                $(".secondaryNav").css("display","none");
              } 
              else {
//secondaryNav disappears when scrolled up
               $(".secondaryNav").css("display","block");
              }
              //Updates scroll position
              lastScroll = st;
          });
0

Here is a simple and usually useful way to show and hide a specific div when moving your mouse:

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
#myDIV {
  width: 100%;
  padding: 50px 0;
  text-align: center;
  background-color: lightblue;
  margin-top: 20px;
}
</style>
</head>
<body>


<button onmousewheel="myFunction()">wheel mouse on me to hide and show div</button>

<div id="myDIV">
This is my DIV element.
</div>

<p><b>Note:</b> The element will not take up any space when the display property set to "none".</p>

<script>
function myFunction() {
  var x = document.getElementById("myDIV");
  if (x.style.display === "none") {
    x.style.display = "block";
  } else {
    x.style.display = "none";
  }
}
</script>

</body>
</html>
0
source

Source: https://habr.com/ru/post/1534859/

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