JSFiddle - React, Tailwind, and code Playground

HTML

<div id="search-container">
    <input type="text" name="search" id="search" />
    <input type="text" disabled="disabled" id="suggestion" />
</div>

CSS

* { margin: 0; padding: 0; }

#search-container {
    position: relative;
}

#search-container input {

    padding: 5px;
    font-size: 1.2em;
    width: 200px;
}

#search {
    position: relative;
    color: #000;
    z-index: 10;
    border: 1px solid #666;
    background: transparent;
}

#suggestion {
    position: absolute;
    top: 0;
    left: 0;
    z-index: 0;
    color: #ccc;
    background: transparent;
    border: 1px solid #fff;
}

JavaScript

$(function() {

    var haystack = [
        "ActionScript",
        "AppleScript",
        "Asp",
        "BASIC",
        "C",
        "C++",
        "Clojure",
        "COBOL",
        "ColdFusion",
        "Erlang",
        "Fortran",
        "Groovy",
        "Haskell",
        "Java",
        "JavaScript",
        "Lisp",
        "Perl",
        "PHP",
        "Python",
        "Ruby",
        "Scala",
        "Scheme"
        ];

    $('#search').keyup(function(e) {
        // 'enter' key was pressed
        var $suggest = $('#suggestion');
        var code = (e.keyCode ? e.keyCode : e.which);
        if(code == 13) {
            $(this).val($suggest.val());
            $suggest.val("");
            return false;
        }

        // some other key was pressed
        var needle = $(this).val();

        // is the field empty?
        if (!$.trim(needle).length) {
            $suggest.val("");
            return false;
        }

        // compare input with haystack
        $.each(haystack, function(i, term) {
            var regex = new RegExp('^' + needle, 'i');
            if (regex.test(term)) {
                $suggest.val(needle + term.slice(needle.length));
                // use first result
                return false;
            }
            $suggest.val("");
        });
    });

});