JSFiddle - React, Tailwind, and code Playground

HTML

<p>Enter no more than 10 words:</p>
<textarea id="myText"></textarea>

CSS

textarea {
    width: 300px;
    height: 100px;     
}

JavaScript

$(document).ready(function($) {
    var max = 10;

    $('#myText').keyup(function(e) {

        if (e.which < 0x20) {
            return;
        }

        var value = $('#myText').val();
        var words = value.trim().split(/\s+/gi);
        var wordCount = words.length;

        if (wordCount == max) {
            // Reached max, prevent additional.
            e.preventDefault();
        } else if (wordCount > max) {
            var substring = words.slice(0, max).join(' ');
            $("#myText").val(substring + ' ');
        }
    });         
});