Get value of remote JS var with Jurassic Script Engine

Question

My remote js file as below

(function(window,document){

    var config =  {
        'placeHolder' : 'content_div'

    };

    var html = "blaaa blaaa";

})(window,document);

I would likte to get value of html. I have tried as below but I have got error.

  string _JsVars = this._HttpWebRequestRemoteUrl(@"http://www.remotewebpage.com");

  var engine = new Jurassic.ScriptEngine();
  var result = engine.(_JsVars);
  var var1 = engine.GetGlobalValue<string>("html");

  MessageBox.Show(var1.ToString());