JSFiddle - React, Tailwind, and code Playground

HTML

<a class="addUrl">click to add url to you textarea</a><br>
<div id="addUrl">
please enter you URLs:<input type="text" id="u"/><input type="button" value="add" id="su"/><input type="button" value="x"/>
</div>
<textarea name="content"></textarea>

CSS

textarea{width:300px;height:300px}
a{color:#390}
#addUrl{display:none}

JavaScript

$(function(){
        $(".addUrl").click(function(){
            $("#addUrl").slideDown();
        })
        $('#su').click(function(){
            if($("#u").val().length>3)
            addUrl($("#u").val());
            $("#u").val("");
        })
        $("input[value=\"x\"]").click(function(){$("#addUrl").fadeOut();})
    })
    function addUrl(e)
    {
        patt="http[s]*:\/\/";
        if(e.match(patt))
            u=e;
        else
            u="http://"+e;
        $("textarea[name=\"content\"]").append("\n\r[url]"+u+"[/url]\n\r");
    }