JSFiddle - React, Tailwind, and code Playground

HTML

<div id = 'container'>
    <div id = 'popUp'></div>
    <div id = 'popUpText'>
        Text
    </div>
</div>

CSS

#container{
    width: 500px;
    height: 200px;
    background: #CCC;
    position: relative;
}

#popUpText
{
    display: none;
    position: absolute;
    bottom: 10px;
    right: 20px;    
}

#popUp{
    display: none;
    right: 20px;
    position: absolute;
    bottom: -32px;
    right: -2px;
    width: 0;
    height: 0;
    border-top: 60px solid transparent;
    border-bottom: 60px solid transparent;
    border-left: 60px solid green;
    -moz-transform: rotate(45deg);
    -o-transform: rotate(45deg);
    -webkit-transform: rotate(45deg);
    transform: rotate(45deg);
}

JavaScript

var h = false;
$("#container").hover(function(){
    if (h == false){
        $("#popUp").fadeIn();
        $("#popUpText").fadeIn();
        h = true;
    }
},function(){
    if (h == true){
        $("#popUp").fadeOut();
        $("#popUpText").fadeOut(function(){h=false});
    }
});