JSFiddle - React, Tailwind, and code Playground

HTML

<form>
    <input id="in" />
</form>
<div id="x">
    Aldor
    Aleph
    Algae
    Algo
    Algol
    Alma-0
    Alphard
    Altran
</div><button id="checker">check!</button>

JavaScript

$(function() {
    var $checker = $('#checker');

    $checker.click(function(ev) {
        var inputFieldVal = $.trim($('#in').val());
        console.log(inputFieldVal); // Alg
        var regExpPattern = '^' + inputFieldVal,
            re = new RegExp(regExpPattern, 'igm');
        console.log(re); // /^Al/gim
        // Get text out of div#x
        var text = $('#x').text();
        // Trim and 'convert' to an array...
        text = $.trim(text).split('\n');
        console.log(text); // ["Aldor", "Aleph", "Algae", "Algo", "Algol", "Alma-0", "Alphard", "Altran"]
        for (var index = 0, upper = text.length; index < upper; ++index) {
            console.log(
            re.test(text[index].trim()), text[index]);
        }
    });
})