<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="./my.html">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>

<script>

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";
}
}
}
</script>

<style>
.dropbtn {
background-color: #4CAF50;
color: white;
padding: 16px;
font-size: 16px !important;
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 !important;
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: none;
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;}

.show {display: block;}
</style>