JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html> 
<title>Mandelbrot set</title>

<div id="out" style="font-size:1px;width:200px;word-wrap:break-word"></div>

JavaScript

// This is a 140byt.es entry, hosted at https://gist.github.com/1257323 
  // initiated by @sylvinus, golfed down to death by @fgnass !

var myFunction =
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
function(w,s,r,i,k,n){for(n=w*w;n--;s.push('█'.fontcolor("#"+k*9)))for(r=i=k=0;r*r+i*i+k++<w;i=t)t=2*r*i+1-2*n/(w*w),r=r*r-i*i+1-3*n/w%3}



var html = [];
myFunction(200, html);
out.innerHTML = html.join('');