Search filter in DropDown using js

Dropdown list in search filter is used for easily search what they want. Don't need to scroll-up - scroll-down for for select any.  
Here,i share css html and script for making search filter in drop down list.
Script and HTML: 


<div class="dropdown">
<button onclick="myFunction()" class="dropbtn">country</button>
  <div id="myDropdown" class="dropdown-content">
    <input type="text" placeholder="Search.." id="myInput" onkeyup="filterFunction()">
    <a href="#about"></a>
    <a href="#base">India </a>
    <a href="#blog">USA</a>
    <a href="#contact">Japan</a>
    <a href="#custom">Tokiyo</a>
    <a href="#support">France</a>
    <a href="#tools">China</a>
     <a href="#custom">Brazil</a>
    <a href="#support">Canada</a>
    <a href="#tools">Denmark</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++) {
        if (a[i].innerHTML.toUpperCase().indexOf(filter) > -1) {
            a[i].style.display = "";
        } else {
            a[i].style.display = "none";
        }
    }
}

</script>

CSS:

.dropbtn {
    background-color: #8b8ff7;
    color: #1f191c;
    padding: 14px;
    font-size: 18px;
    border: none;
    cursor: pointer;
    margin-left: 100px;
    margin-top: 20px;
}
.dropbtn:hover, .dropbtn:focus {
    background-color: #a9b2f1;
}
#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: 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;

}

OutPut:

India USA Japan Tokiyo France China Brazil Canada Denmark

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