JSFiddle - React, Tailwind, and code Playground

HTML

<input id="search" type="text" name="search" value="" />

<div class="checkbox">
   <label>
   <input type="checkbox" class="chkItem" name="Selected" value="1" /> A
   </label>
</div>
<div class="checkbox">
   <label>
   <input type="checkbox" class="chkItem" name="Selected" value="2" /> B
   </label>
</div>
<div class="checkbox">
   <label>
   <input type="checkbox" class="chkItem" name="Selected" value="3" /> C
   </label>
</div>

JavaScript

$("#search").bind("change keyup", function() {
    var search_str = $(this).val().toLowerCase();
    if (search_str != "") {
        $(".checkbox").hide();
        $(".checkbox").filter(function( index ) {
            return $( this ).text().toLowerCase().indexOf(search_str) != -1;
        }).show();
    } else {
        $(".checkbox").show();
    }
});