JSFiddle - React, Tailwind, and code Playground

HTML

<textarea placeholder="Reply box 2..." columns="10" rows="1" name="comment-input"></textarea>
            <input type="submit" id="submit" value="Send" disabled>

JavaScript

$('textarea[name=comment-input]').keyup(function(e){
    $(this).parent().find("#submit").attr("disabled", true);
    val = $(this).val().trim();    
    if(val.length > 0){
        $(this).parent().find("#submit").attr("disabled", false);
    }
});