Load Typekit if fonts not already loaded

gistfile1.js

// Set kit ID
var typekitID = "tk999999";
var testFont = "wf-proximanova-n4-active";

// Wait... then load Typekit if font not active
setTimeout("addTypekit(typekitID);",3000);


function addTypekit(typekitID,testFont){

  // If HTML element doesn't have font's success class, load Typekit
  var htmlElement = document.getElementsByTagName("html")[0]
  if((' ' + htmlElement.className + ' ').indexOf(' ' + testFont + ' ') == -1){

    WebFontConfig = {
      typekit: { id: typekitID }
    };

    (function() {
      var wf = document.createElement('script');
      wf.src = ('https:' == document.location.protocol ? 'https' : 'http') +
          '://ajax.googleapis.com/ajax/libs/webfont/1.4.7/webfont.js';
      wf.type = 'text/javascript';
      wf.async = 'true';
      var s = document.getElementsByTagName('script')[0];
      s.parentNode.insertBefore(wf, s);
    })();

    console.log('font loaded by navbar');

  }
  else{
    console.log('font loaded by page');
  }
}