JSFiddle - React, Tailwind, and code Playground

HTML

<div>

</div>

CSS

div { position:relative; background-color:#333; padding:20px; margin:20px; float:left; }

div:before { content:""; display:block; padding:5px; background-color:#f60; border:2px solid white; position: absolute; top:-2px; right:-2px; border-bottom-left-radius: 10px; }

JavaScript

$("div").click(function(e){
    var $me = $(this),
        width = $me.outerWidth(),
        height = $me.outerHeight(),
        top = $me.position().top,
        left = $me.position().left;
                    
    var len = Math.sqrt(Math.pow(width - e.offsetX, 2) + Math.pow(e.offsetY, 2));

    if (len < 10)
        alert('ding');
});