<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<!------ Include the above in your HEAD tag ---------->
<h5>Click on the button to open the dropdown menu,
and use the input field to search for a specific
dropdown link.</h5>
<div class="dropdown" >
<button onclick="myFunction()" class="dropbtn">Dropdown</button>
<div id="myDropdown" class="dropdown-content">
<input type="text" placeholder="Search.." id="myInput" onkeyup="filterFunction()">
<a href="#about">About</a>
<a href="#base">Base</a>
<a href="#blog">Blog</a>
<a href="#contact">Contact</a>
<a href="#custom">Custom</a>
<a href="#support">Support</a>
<a href="#tools">Tools</a>
</div>
</div>
/* When the user clicks on the button,
toggle between hiding and showing the dropdown content */
function myFunction() {
document.getElementById("myDropdown").classList.toggle("show");
}
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++) {
txtValue = a[i].textContent || a[i].innerText;
if (txtValue.toUpperCase().indexOf(filter) > -1) {
a[i].style.display = "";
} else {
a[i].style.display = "none";
}
}
}