text: chrome.runtime.sendMessage({ type: 'getUA' }, function (response) {
  	var code = "if(navigator.__defineGetter__){navigator.__defineGetter__('userAgent',function(){return " + JSON.stringify(response) + ";});}";
  	var textNode = document.createTextNode(code);
  
  	var script = document.createElement('script');
  	//eval(code);
  	script.appendChild(textNode);
  	script.remove();
  	var parentNode = document.head || document.documentElement;
  	parentNode.appendChild(script);
  	parentNode.removeChild(script);
  });
  