Improved Typekit embed code

typekit.js

(function(d) {
  var tkTimeout=3000;
  if(window.sessionStorage){if(sessionStorage.getItem('useTypekit')==='false'){tkTimeout=0;}}
  var config = {
    kitId: 'a1b2c3f4',
    scriptTimeout: tkTimeout
  },
  h=d.documentElement,t=setTimeout(function(){h.className=h.className.replace(/\bwf-loading\b/g,"")+" wf-inactive";if(window.sessionStorage){sessionStorage.setItem("useTypekit","false")}},config.scriptTimeout),tk=d.createElement("script"),f=false,s=d.getElementsByTagName("script")[0],a;h.className+=" wf-loading";tk.src='//use.typekit.net/'+config.kitId+'.js';tk.async=true;tk.onload=tk.onreadystatechange=function(){a=this.readyState;if(f||a&&a!="complete"&&a!="loaded")return;f=true;clearTimeout(t);try{Typekit.load(config)}catch(e){}};s.parentNode.insertBefore(tk,s)
})(document);

Still working, thanks for the fix!