JSFiddle - React, Tailwind, and code Playground

HTML

<form name="save" method="post" action="save.php">
    <input width="100%" name="title" type="text" id="title" value="Untitled Written" placeholder="Title">
    <input type="submit" name="save" value="Save">
    <div>
        <textarea rows="8" cols="3" class="alignright" name="set_a_syllable_count" /></textarea>
        <textarea class="writer" name="set_a">There should be "0" to the left below this line&#013;&#010;&#013;&#010;But there isn't...</textarea>
    </div>
</form>

CSS

.alignright {
    width:5%;
    height:72vh;
    resize: none;
    float:left;
    border:none;
    overflow:hidden;
}
.alignright:focus {
    outline: none !important;
    border-color:none;
    border:none;
    box-shadow:none;
}
.writer {
    height:72vh;
    width:400px;
    float:left;
}

JavaScript

function $count_how_many_syllables($input) {
    $("[name=set_" + $input + "]").keyup(function () {

        var arrayOfLines = $("[name=set_" + $input + "]").val().match(/[^\r\n]+/g);
        var $content;
        var $word = 0;
        var $syllable_count = "";
        var $result = "";

        for (var i = 0; i < arrayOfLines.length; i++) {
            $content = arrayOfLines[i].toLowerCase();
            word = $content.replace(/(?:[^laeiouy]es|ed|[^laeiouy]e)$/, '')
                .replace(/^y/, '')
                .match(/[aeiouy]/g).length;
            if ($content.length <= 3) {
                word = 1;
            }
            if (word !== 0) {
                $syllable_count = word.toString();
                $result = $result + $syllable_count + "\n";
            } else {
                $result = $result + "0 \n";
            }
        }

        $("[name=set_" + $input + "_syllable_count]").val($result);
        // set scrolling
        $("[name=set_" + $input + "_syllable_count]").scrollTop = $("[name=set_" + $input + "]").scrollTop;
        $("[name=set_" + $input + "_syllable_count]").scrollLeft = $("[name=set_" + $input + "]").scrollLeft;
    });
}

(function ($) {
    $count_how_many_syllables("a");
})(jQuery);