JSFiddle - React, Tailwind, and code Playground

HTML

<div id="myDropdown" class="dropdown-content">
  <input type="text" placeholder="Search.." id="myInput" onkeyup="filterFunction()">
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</div>

<p>
 Kopiert und verändert aus:<br>https://www.w3schools.com/howto/tryit.asp?filename=tryhow_css_js_dropdown_filter
</p>

CSS

.dropbtn {
    background-color: #4CAF50;
    color: white;
    padding: 16px;
    font-size: 16px;
    border: none;
    cursor: pointer;
}

.dropbtn:hover, .dropbtn:focus {
    background-color: #3e8e41;
}

#myInput {
    border-box: box-sizing;
    background-image: url('searchicon.png');
    background-position: 14px 12px;
    background-repeat: no-repeat;
    font-size: 16px;
    padding: 14px 20px 12px 45px;
    border: none;
    border-bottom: 1px solid #ddd;
}

#myInput:focus {outline: 3px solid #ddd;}

.dropdown {
    position: relative;
    display: inline-block;
}

.dropdown-content {
    display: block;
    position: absolute;
    background-color: #f6f6f6;
    min-width: 230px;
    overflow: auto;
    border: 1px solid #ddd;
    z-index: 1;
}

.dropdown-content a {
    color: black;
    padding: 12px 16px;
    text-decoration: none;
    display: block;
}

.dropdown a:hover {background-color: #ddd;}

p {
  position: fixed;
  bottom: 0;
}

JavaScript

function filterFunction() {
  var input, filter, ul, li, a, i;
  input = document.getElementById("myInput");
  filter = input.value.toUpperCase();
  div = document.getElementById("myDropdown");
  a = div.getElementsByTagName("a");
  for (i = 0; i < a.length; i++) {
    if (a[i].innerHTML.toUpperCase().indexOf(filter) > -1) {
      a[i].style.display = "";
    } else {
      a[i].style.display = "none";
    }
  }
}