Font Loaded fires an event when "FontAwesome" has been loaded.

fontLoaded.js

  // Font Loaded
  (function fontLoaded() {
    var retries = 300;

    function checkReady() {
      var canvas,
          context;
      retries -= 1;
      canvas = document.createElement('canvas');
      canvas.width = 20;
      canvas.height = 20;
      context = canvas.getContext('2d');
      context.fillStyle = 'rgba(0,0,0,1.0)';
      context.fillRect( 0, 0, 20, 20 );
      context.font = '16pt FontAwesome';
      context.textAlign = 'center';
      context.fillStyle = 'rgba(255,255,255,1.0)';
      context.fillText( '\uf0c8', 10, 18 );
      var data = context.getImageData( 2, 10, 1, 1 ).data;
      if ( data[0] !== 255 && data[1] !== 255 && data[2] !== 255 ) {
        // FontAwesome is not yet available, retrying ...
        if ( retries > 0 ) {
          setTimeout( checkReady, 100 );
        } else {
          // failed
        }
      } else {
        var customEvent;
        if (window.CustomEvent) {
          customEvent = new CustomEvent('fontLoaded', {detail: {}});
        } else {
          customEvent = document.createEvent('CustomEvent');
          customEvent.initCustomEvent('fontLoaded', true, true, {});
        }
        document.dispatchEvent(customEvent);
      }
    }
    checkReady();
  }());